DSA450.md

Questions by Love Babbar (DSA 450 sheet)

Youtube Channel: https://www.youtube.com/channel/UCQHLxxBFrbfdrk1jF0moTpw

Sr. No.	Topic	Problem	Comments
1	Array	Reverse the array
2	Array	Find the maximum and minimum element in an array
3	Array	Find the "Kth" max and min element of an array
4	Array	Given an array which consists of only 0, 1 and 2. Sort the array without using any sorting algo
5	Array	Move all the negative elements to one side of the array
6	Array	Find the Union and Intersection of the two sorted arrays.
7	Array	Write a program to cyclically rotate an array by one.
8	Array	find Largest sum contiguous Subarray [V. IMP]
9	Array	Minimise the maximum difference between heights [V.IMP]
10	Array	Minimum no. of Jumps to reach end of an array
11	Array	find duplicate in an array of N+1 Integers
12	Array	Merge 2 sorted arrays without using Extra space.
13	Array	Kadane's Algo [V.V.V.V.V IMP]
14	Array	Merge Intervals
15	Array	Next Permutation
16	Array	Count Inversion
17	Array	Best time to buy and Sell stock
18	Array	find all pairs on integer array whose sum is equal to given number
19	Array	find common elements In 3 sorted arrays
20	Array	Rearrange the array in alternating positive and negative items with O(1) extra space
21	Array	Find if there is any subarray with sum equal to 0
22	Array	Find factorial of a large number
23	Array	find maximum product subarray
24	Array	Find longest consecutive subsequence
25	Array	Given an array of size n and a number k, fin all elements that appear more than " n/k " times.
26	Array	Maximum profit by buying and selling a share atmost twice
27	Array	Find whether an array is a subset of another array
28	Array	Find the triplet that sum to a given value
29	Array	Trapping Rain water problem
30	Array	Chocolate Distribution problem
31	Array	Smallest Subarray with sum greater than a given value
32	Array	Three way partitioning of an array around a given value
33	Array	Minimum swaps required bring elements less equal K together
34	Array	Minimum no. of operations required to make an array palindrome
35	Array	Median of 2 sorted arrays of equal size
36	Array	Median of 2 sorted arrays of different size
37	Matrix	Spiral traversal on a Matrix
38	Matrix	Search an element in a matrix
39	Matrix	Find median in a row wise sorted matrix
40	Matrix	Find row with maximum no. of 1's
41	Matrix	Print elements in sorted order using row-column wise sorted matrix (generalised form: MxN matrix)	Can’t solve generalized form MxN in given time (NOT DONE)
42	Matrix	Maximum size rectangle	Area of histogram bugged me a lot
43	Matrix	Find the maximum difference in the matrix (find specific pair in a matrix)
44	Matrix	Rotate a matrix by 90deg
45	Matrix	Kth smallest element in a row-column wise sorted matrix	Algorithm wasn’t quite intuitive
46	Matrix	Common elements in all rows of a given matrix
47	String	Reverse a String
48	String	Check whether a String is Palindrome or not
49	String	Find Duplicate characters in a string
50	String	Why strings are immutable in Java?	Because of the ‘String Constant Pool’ concept
51	String	Write a Code to check whether one string is a rotation of another
52	String	Write a Program to check whether a string is a valid shuffle of two strings or not
53	String	Count and Say problem	Nice one !
54	String	Write a program to find the longest Palindrome in a string.[ Longest palindromic Substring]
55	String	Find Longest Recurring Subsequence in String
56	String	Print all Subsequences of a string.
57	String	Print all the permutations of the given string
58	String	Split the Binary string into two substring with equal 0’s and 1’s
59	String	Word Wrap Problem [VERY IMP].	I solved the problem without extra space but in O(2n) However I will try the DP solution too
60	String	EDIT Distance [Very Imp]
61	String	Find next greater number with same set of digits. [Very Very IMP]	[Repeated] - Array Q15
62	String	Balanced Parenthesis problem.[Imp]
63	String	Word break Problem[ Very Imp]	A good one
64	String	Rabin Karp Algo	doubt: Why mod = 1e9+7 gave the wrong answer, but 1e5+7 worked fine [ANSWERED]
65	String	KMP Algo	V.Important
66	String	Convert a Sentence into its equivalent mobile numeric keypad sequence.
67	String	Minimum number of bracket reversals needed to make an expression balanced.
68	String	Count All Palindromic Subsequence in a given String.
69	String	Count of number of given string in 2D character array	POTENTIAL CROSSWORD SOLVER ? Checkout the resources folder for what I made before solving this
70	String	Search a Word in a 2D Grid of characters.
71	String	Boyer Moore Algorithm for Pattern Searching.	Another good one
72	String	Converting Roman Numerals to Decimal
73	String	Longest Common Prefix
74	String	Number of flips to make binary string alternate
75	String	Find the first repeated word in string.
76	String	Minimum number of swaps for bracket balancing.
77	String	Find the longest common subsequence between two strings.
78	String	Program to generate all possible valid IP addresses from given string.
79	String	Write a program tofind the smallest window that contains all characters of string itself.
80	String	Rearrange characters in a string such that no two adjacent are same
81	String	Minimum characters to be added at front to make string palindrome
82	String	Given a sequence of words, print all anagrams together
83	String	Find the smallest window in a string containing all characters of another string
84	String	Recursively remove all adjacent duplicates
85	String	String matching where one string contains wildcard characters
86	String	Function to find Number of customers who could not get a computer
87	String	Transform One String to Another using Minimum Number of Given Operation
88	String	Check if two given strings are isomorphic to each other
89	String	Recursively print all sentences that can be formed from list of word lists
90	Searching & Sorting	Find first and last positions of an element in a sorted array
91	Searching & Sorting	Find a Fixed Point (Value equal to index) in a given array
92	Searching & Sorting	Search in a rotated sorted array
93	Searching & Sorting	square root of an integer
94	Searching & Sorting	Maximum and minimum of an array using minimum number of comparisons
95	Searching & Sorting	Optimum location of point to minimize total distance
96	Searching & Sorting	Find the repeating and the missing
97	Searching & Sorting	find majority element
98	Searching & Sorting	Searching in an array where adjacent differ by at most k
99	Searching & Sorting	find a pair with a given difference
100	Searching & Sorting	find four elements that sum to a given value
101	Searching & Sorting	maximum sum such that no 2 elements are adjacent
102	Searching & Sorting	Count triplet with sum smaller than a given value
103	Searching & Sorting	merge 2 sorted arrays
104	Searching & Sorting	print all subarrays with 0 sum
105	Searching & Sorting	Product array Puzzle
106	Searching & Sorting	Sort array according to count of set bits
107	Searching & Sorting	minimum no. of swaps required to sort the array
108	Searching & Sorting	Bishu and Soldiers
109	Searching & Sorting	Rasta and Kheshtak
110	Searching & Sorting	Kth smallest number again
111	Searching & Sorting	Find pivot element in a sorted array
112	Searching & Sorting	K-th Element of Two Sorted Arrays
113	Searching & Sorting	Aggressive cows
114	Searching & Sorting	Book Allocation Problem
115	Searching & Sorting	EKOSPOJ:
116	Searching & Sorting	Job Scheduling Algo
117	Searching & Sorting	Missing Number in AP
118	Searching & Sorting	Smallest number with atleastn trailing zeroes infactorial
119	Searching & Sorting	Painters Partition Problem:
120	Searching & Sorting	ROTI-Prata SPOJ
121	Searching & Sorting	DoubleHelix SPOJ
122	Searching & Sorting	Subset Sums
123	Searching & Sorting	Findthe inversion count
124	Searching & Sorting	Implement Merge-sort in-place
125	Searching & Sorting	Partitioning and Sorting Arrays with Many Repeated Entries
126	LinkedList	Write a Program to reverse the Linked List. (Both Iterative and recursive)
127	LinkedList	Reverse a Linked List in group of Given Size. [Very Imp]
128	LinkedList	Write a program to Detect loop in a linked list.
129	LinkedList	Write a program to Delete loop in a linked list.
130	LinkedList	Find the starting point of the loop.
131	LinkedList	Remove Duplicates in a sorted Linked List.
132	LinkedList	Remove Duplicates in a Un-sorted Linked List.
133	LinkedList	Write a Program to Move the last element to Front in a Linked List.
134	LinkedList	Add “1” to a number represented as a Linked List.
135	LinkedList	Add two numbers represented by linked lists.
136	LinkedList	Intersection of two Sorted Linked List.
137	LinkedList	Intersection Point of two Linked Lists.
138	LinkedList	Merge Sort For Linked lists.[Very Important]
139	LinkedList	Quicksort for Linked Lists.[Very Important]
140	LinkedList	Find the middle Element of a linked list.
141	LinkedList	Check if a linked list is a circular linked list.
142	LinkedList	Split a Circular linked list into two halves.
143	LinkedList	Write a Program to check whether the Singly Linked list is a palindrome or not.
144	LinkedList	Deletion from a Circular Linked List.
145	LinkedList	Reverse a Doubly Linked list.
146	LinkedList	Find pairs with a given sum in a DLL.
147	LinkedList	Count triplets in a sorted DLL whose sum is equal to given value “X”.
148	LinkedList	Sort a “k”sorted Doubly Linked list.[Very IMP]
149	LinkedList	Rotate DoublyLinked list by N nodes.
150	LinkedList	Rotate a Doubly Linked list in group of Given Size.[Very IMP]
151	LinkedList	Can we reverse a linked list in less than O(n) ?
152	LinkedList	Why Quicksort is preferred for. Arrays and Merge Sort for LinkedLists ?
153	LinkedList	Flatten a Linked List
154	LinkedList	Sort a LL of 0's, 1's and 2's
155	LinkedList	Clone a linked list with next and random pointer
156	LinkedList	Merge K sorted Linked list
157	LinkedList	Multiply 2 no. represented by LL
158	LinkedList	Delete nodes which have a greater value on right side
159	LinkedList	Segregate even and odd nodes in a Linked List
160	LinkedList	Program for n’th node from the end of a Linked List
161	LinkedList	Find the first non-repeating character from a stream of characters
162	Binary Trees	level order traversal
163	Binary Trees	Reverse Level Order traversal
164	Binary Trees	Height of a tree
165	Binary Trees	Diameter of a tree
166	Binary Trees	Mirror of a tree
167	Binary Trees	Inorder Traversal of a tree both using recursion and Iteration
168	Binary Trees	Preorder Traversal of a tree both using recursion and Iteration
169	Binary Trees	Postorder Traversal of a tree both using recursion and Iteration
170	Binary Trees	Left View of a tree
171	Binary Trees	Right View of Tree
172	Binary Trees	Top View of a tree
173	Binary Trees	Bottom View of a tree
174	Binary Trees	Zig-Zag traversal of a binary tree
175	Binary Trees	Check if a tree is balanced or not
176	Binary Trees	Diagnol Traversal of a Binary tree
177	Binary Trees	Boundary traversal of a Binary tree
178	Binary Trees	Construct Binary Tree from String with Bracket Representation
179	Binary Trees	Convert Binary tree into Doubly Linked List
180	Binary Trees	Convert Binary tree into Sum tree
181	Binary Trees	Construct Binary tree from Inorder and preorder traversal
182	Binary Trees	Find minimum swaps required to convert a Binary tree into BST
183	Binary Trees	Check if Binary tree is Sum tree or not
184	Binary Trees	Check if all leaf nodes are at same level or not
185	Binary Trees	Check if a Binary Tree contains duplicate subtrees of size 2 or more [IMP]
186	Binary Trees	Check if 2 trees are mirror or not
187	Binary Trees	Sum of Nodes on the Longest path from root to leaf node
188	Binary Trees	Check if given graph is tree or not. [IMP]
189	Binary Trees	Find Largest subtree sum in a tree
190	Binary Trees	Maximum Sum of nodes in Binary tree such that no two are adjacent
191	Binary Trees	Print all "K" Sum paths in a Binary tree
192	Binary Trees	Find LCA in a Binary tree
193	Binary Trees	Find distance between 2 nodes in a Binary tree
194	Binary Trees	Kth Ancestor of node in a Binary tree
195	Binary Trees	Find all Duplicate subtrees in a Binary tree [ IMP ]
196	Binary Trees	Tree Isomorphism Problem
197	Binary Search Trees	Fina a value in a BST
198	Binary Search Trees	Deletion of a node in a BST
199	Binary Search Trees	Find min and max value in a BST
200	Binary Search Trees	Find inorder successor and inorder predecessor in a BST
201	Binary Search Trees	Check if a tree is a BST or not
202	Binary Search Trees	Populate Inorder successor of all nodes
203	Binary Search Trees	Find LCA of 2 nodes in a BST
204	Binary Search Trees	Construct BST from preorder traversal
205	Binary Search Trees	Convert Binary tree into BST
206	Binary Search Trees	Convert a normal BST into a Balanced BST
207	Binary Search Trees	Merge two BST [ V.V.V>IMP ]
208	Binary Search Trees	Find Kth largest element in a BST
209	Binary Search Trees	Find Kth smallest element in a BST
210	Binary Search Trees	Count pairs from 2 BST whose sum is equal to given value "X"
211	Binary Search Trees	Find the median of BST in O(n) time and O(1) space
212	Binary Search Trees	Count BST ndoes that lie in a given range
213	Binary Search Trees	Replace every element with the least greater element on its right
214	Binary Search Trees	Given "n" appointments, find the conflicting appointments
215	Binary Search Trees	Check preorder is valid or not
216	Binary Search Trees	Check whether BST contains Dead end
217	Binary Search Trees	Largest BST in a Binary Tree [ V.V.V.V.V IMP ]
218	Binary Search Trees	Flatten BST to sorted list
219	Greedy	Activity Selection Problem
220	Greedy	Job SequencingProblem
221	Greedy	Huffman Coding
222	Greedy	Water Connection Problem
223	Greedy	Fractional Knapsack Problem
224	Greedy	Greedy Algorithm to find Minimum number of Coins
225	Greedy	Maximum trains for which stoppage can be provided
226	Greedy	Minimum Platforms Problem
227	Greedy	Buy Maximum Stocks if i stocks can be bought on i-th day
228	Greedy	Find the minimum and maximum amount to buy all N candies
229	Greedy	Minimize Cash Flow among a given set of friends who have borrowed money from each other
230	Greedy	Minimum Cost to cut a board into squares
231	Greedy	Check if it is possible to survive on Island
232	Greedy	Find maximum meetings in one room
233	Greedy	Maximum product subset of an array
234	Greedy	Maximize array sum after K negations
235	Greedy	Maximize the sum of arr[i]*i
236	Greedy	Maximum sum of absolute difference of an array
237	Greedy	Maximize sum of consecutive differences in a circular array
238	Greedy	Minimum sum of absolute difference of pairs of two arrays
239	Greedy	Program for Shortest Job First (or SJF) CPU Scheduling
240	Greedy	Program for Least Recently Used (LRU) Page Replacement algorithm
241	Greedy	Smallest subset with sum greater than all other elements
242	Greedy	Chocolate Distribution Problem
243	Greedy	DEFKIN -Defense of a Kingdom
244	Greedy	DIEHARD -DIE HARD
245	Greedy	GERGOVIA -Wine trading in Gergovia
246	Greedy	Picking Up Chicks
247	Greedy	CHOCOLA –Chocolate
248	Greedy	ARRANGE -Arranging Amplifiers
249	Greedy	K Centers Problem
250	Greedy	Minimum Cost of ropes
251	Greedy	Find smallest number with given number of digits and sum of digits
252	Greedy	Rearrange characters in a string such that no two adjacent are same
253	Greedy	Find maximum sum possible equal sum of three stacks
254	BackTracking	Rat in a maze Problem
255	BackTracking	Printing all solutions in N-Queen Problem
256	BackTracking	Word Break Problem using Backtracking
257	BackTracking	Remove Invalid Parentheses
258	BackTracking	Sudoku Solver
259	BackTracking	m Coloring Problem
260	BackTracking	Print all palindromic partitions of a string
261	BackTracking	Subset Sum Problem
262	BackTracking	The Knight’s tour problem
263	BackTracking	Tug of War
264	BackTracking	Find shortest safe route in a path with landmines
265	BackTracking	Combinational Sum
266	BackTracking	Find Maximum number possible by doing at-most K swaps
267	BackTracking	Print all permutations of a string
268	BackTracking	Find if there is a path of more than k length from a source
269	BackTracking	Longest Possible Route in a Matrix with Hurdles
270	BackTracking	Print all possible paths from top left to bottom right of a mXn matrix
271	BackTracking	Partition of a set intoK subsets with equal sum
272	BackTracking	Find the K-th Permutation Sequence of first N natural numbers
273	Stacks & Queues	Implement Stack from Scratch
274	Stacks & Queues	Implement Queue from Scratch
275	Stacks & Queues	Implement 2 stack in an array
276	Stacks & Queues	find the middle element of a stack
277	Stacks & Queues	Implement "N" stacks in an Array
278	Stacks & Queues	Check the expression has valid or Balanced parenthesis or not.
279	Stacks & Queues	Reverse a String using Stack
280	Stacks & Queues	Design a Stack that supports getMin() in O(1) time and O(1) extra space.
281	Stacks & Queues	Find the next Greater element
282	Stacks & Queues	The celebrity Problem
283	Stacks & Queues	Arithmetic Expression evaluation.)
284	Stacks & Queues	Evaluation of Postfix expression
285	Stacks & Queues	Implement a method to insert an element at its bottom without using any other data structure.
286	Stacks & Queues	Reverse a stack using recursion
287	Stacks & Queues	Sort a Stack using recursion
288	Stacks & Queues	Merge Overlapping Intervals
289	Stacks & Queues	Largest rectangular Area in Histogram
290	Stacks & Queues	Length of the Longest Valid Substring
291	Stacks & Queues	Expression contains redundant bracket or not
292	Stacks & Queues	Implement Stack using Queue
293	Stacks & Queues	Implement Stack using Deque
294	Stacks & Queues	Stack Permutations (Check if an array is stack permutation of other)
295	Stacks & Queues	Implement Queue using Stack
296	Stacks & Queues	Implement "n" queue in an array
297	Stacks & Queues	Implement a Circular queue
298	Stacks & Queues	LRU Cache Implementationa
299	Stacks & Queues	Reverse a Queue using recursion
300	Stacks & Queues	Reverse the first “K” elements of a queue
301	Stacks & Queues	Interleave the first half of the queue with second half
302	Stacks & Queues	Find the first circular tour that visits all Petrol Pumps
303	Stacks & Queues	Minimum time required to rot all oranges
304	Stacks & Queues	Distance of nearest cell having 1 in a binary matrix
305	Stacks & Queues	First negative integer in every window of size “k”
306	Stacks & Queues	Check if all levels of two trees are anagrams or not.
307	Stacks & Queues	Sum of minimum and maximum elements of all subarrays of size “k”.
308	Stacks & Queues	Minimum sum of squares of character counts in a given string after removing “k” characters.
309	Stacks & Queues	Queue based approach or first non-repeating character in a stream.
310	Stacks & Queues	Next Smaller Element
311	Heap	Implement a Maxheap/MinHeap using arrays and recursion.
312	Heap	Sort an Array using heap. (HeapSort)
313	Heap	Maximum of all subarrays of size k.
314	Heap	“k” largest element in an array
315	Heap	Kth smallest and largest element in an unsorted array
316	Heap	Merge “K” sorted arrays. [ IMP ]
317	Heap	Merge 2 Binary Max Heaps
318	Heap	Kth largest sum continuous subarrays
319	Heap	Leetcode- reorganize strings
320	Heap	Merge “K” Sorted Linked Lists [V.IMP]
321	Heap	Smallest range in “K” Lists
322	Heap	Median in a stream of Integers
323	Heap	Check if a Binary Tree is Heap
324	Heap	Connect “n” ropes with minimum cost
325	Heap	Convert BST to Min Heap
326	Heap	Convert min heap to max heap
327	Heap	Rearrange characters in a string such that no two adjacent are same.
328	Heap	Minimum sum of two numbers formed from digits of an array
329	Graph	Create a Graph, print it
330	Graph	Implement BFS algorithm
331	Graph	Implement DFS Algo
332	Graph	Detect Cycle in Directed Graph using BFS/DFS Algo
333	Graph	Detect Cycle in UnDirected Graph using BFS/DFS Algo
334	Graph	Search in a Maze
335	Graph	Minimum Step by Knight
336	Graph	flood fill algo
337	Graph	Clone a graph
338	Graph	Making wired Connections
339	Graph	word Ladder
340	Graph	Dijkstra algo
341	Graph	Implement Topological Sort
342	Graph	Minimum time taken by each job to be completed given by a Directed Acyclic Graph
343	Graph	Find whether it is possible to finish all tasks or not from given dependencies
344	Graph	Find the no. of Isalnds
345	Graph	Given a sorted Dictionary of an Alien Language, find order of characters
346	Graph	Implement Kruksal’sAlgorithm
347	Graph	Implement Prim’s Algorithm
348	Graph	Total no. of Spanning tree in a graph
349	Graph	Implement Bellman Ford Algorithm
350	Graph	Implement Floyd warshallAlgorithm
351	Graph	Travelling Salesman Problem
352	Graph	Graph ColouringProblem
353	Graph	Snake and Ladders Problem
354	Graph	Find bridge in a graph
355	Graph	Count Strongly connected Components(Kosaraju Algo)
356	Graph	Check whether a graph is Bipartite or Not
357	Graph	Detect Negative cycle in a graph
358	Graph	Longest path in a Directed Acyclic Graph
359	Graph	Journey to the Moon
360	Graph	Cheapest Flights Within K Stops
361	Graph	Oliver and the Game
362	Graph	Water Jug problem using BFS
363	Graph	Water Jug problem using BFS
364	Graph	Find if there is a path of more thank length from a source
365	Graph	M-ColouringProblem
366	Graph	Minimum edges to reverse o make path from source to destination
367	Graph	Paths to travel each nodes using each edge(Seven Bridges)
368	Graph	Vertex Cover Problem
369	Graph	Chinese Postman or Route Inspection
370	Graph	Number of Triangles in a Directed and Undirected Graph
371	Graph	Minimise the cashflow among a given set of friends who have borrowed money from each other
372	Graph	Two Clique Problem
373	Trie	Construct a trie from scratch
374	Trie	Find shortest unique prefix for every word in a given list
375	Trie	Word Break Problem
376	Trie	Given a sequence of words, print all anagrams together
377	Trie	Implement a Phone Directory
378	Trie	Print unique rows in a given boolean matrix
379	Dynamic Programming	Coin ChangeProblem
380	Dynamic Programming	Knapsack Problem
381	Dynamic Programming	Binomial CoefficientProblem
382	Dynamic Programming	Permutation CoefficientProblem
383	Dynamic Programming	Program for nth Catalan Number
384	Dynamic Programming	Matrix Chain Multiplication
385	Dynamic Programming	Edit Distance
386	Dynamic Programming	Subset Sum Problem
387	Dynamic Programming	Friends Pairing Problem
388	Dynamic Programming	Gold Mine Problem
389	Dynamic Programming	Assembly Line SchedulingProblem
390	Dynamic Programming	Painting the Fenceproblem
391	Dynamic Programming	Maximize The Cut Segments
392	Dynamic Programming	Longest Common Subsequence
393	Dynamic Programming	Longest Repeated Subsequence
394	Dynamic Programming	Longest Increasing Subsequence
395	Dynamic Programming	Space Optimized Solution of LCS
396	Dynamic Programming	LCS (Longest Common Subsequence) of three strings
397	Dynamic Programming	Maximum Sum Increasing Subsequence
398	Dynamic Programming	Count all subsequences having product less than K
399	Dynamic Programming	Longest subsequence such that difference between adjacent is one
400	Dynamic Programming	Maximum subsequence sum such that no three are consecutive
401	Dynamic Programming	Egg Dropping Problem
402	Dynamic Programming	Maximum Length Chain of Pairs
403	Dynamic Programming	Maximum size square sub-matrix with all 1s
404	Dynamic Programming	Maximum sum of pairs with specific difference
405	Dynamic Programming	Min Cost PathProblem
406	Dynamic Programming	Maximum difference of zeros and ones in binary string
407	Dynamic Programming	Minimum number of jumps to reach end
408	Dynamic Programming	Minimum cost to fill given weight in a bag
409	Dynamic Programming	Minimum removals from array to make max –min <= K
410	Dynamic Programming	Longest Common Substring
411	Dynamic Programming	Count number of ways to reacha given score in a game
412	Dynamic Programming	Count Balanced Binary Trees of Height h
413	Dynamic Programming	LargestSum Contiguous Subarray [V>V>V>V IMP ]
414	Dynamic Programming	Smallest sum contiguous subarray
415	Dynamic Programming	Unbounded Knapsack (Repetition of items allowed)
416	Dynamic Programming	Word Break Problem
417	Dynamic Programming	Largest Independent Set Problem
418	Dynamic Programming	Partition problem
419	Dynamic Programming	Longest Palindromic Subsequence
420	Dynamic Programming	Count All Palindromic Subsequence in a given String
421	Dynamic Programming	Longest Palindromic Substring
422	Dynamic Programming	Longest alternating subsequence
423	Dynamic Programming	Weighted Job Scheduling
424	Dynamic Programming	Coin game winner where every player has three choices
425	Dynamic Programming	Count Derangements (Permutation such that no element appears in its original position) [ IMPORTANT ]
426	Dynamic Programming	Maximum profit by buying and selling a share at most twice [ IMP ]
427	Dynamic Programming	Optimal Strategy for a Game
428	Dynamic Programming	Optimal Binary Search Tree
429	Dynamic Programming	Palindrome PartitioningProblem
430	Dynamic Programming	Word Wrap Problem
431	Dynamic Programming	Mobile Numeric Keypad Problem [ IMP ]
432	Dynamic Programming	Boolean Parenthesization Problem
433	Dynamic Programming	Largest rectangular sub-matrix whose sum is 0
434	Dynamic Programming	Largest area rectangular sub-matrix with equal number of 1’s and 0’s [ IMP ]
435	Dynamic Programming	Maximum sum rectangle in a 2D matrix
436	Dynamic Programming	Maximum profit by buying and selling a share at most k times
437	Dynamic Programming	Find if a string is interleaved of two other strings
438	Dynamic Programming	Maximum Length of Pair Chain
439	Bit Manipulation	Count set bits in an integer
440	Bit Manipulation	Find the two non-repeating elements in an array of repeating elements
441	Bit Manipulation	Count number of bits to be flipped to convert A to B
442	Bit Manipulation	Count total set bits in all numbers from 1 to n
443	Bit Manipulation	Program to find whether a no is power of two
444	Bit Manipulation	Find position of the only set bit
445	Bit Manipulation	Copy set bits in a range
446	Bit Manipulation	Divide two integers without using multiplication, division and mod operator
447	Bit Manipulation	Calculate square of a number without using *, / and pow()
448	Bit Manipulation	Power Set