From 112812b870d5001bc3b5007249b17d5e0e7e9ff3 Mon Sep 17 00:00:00 2001
From: simran2607 <56145342+simran2607@users.noreply.github.com>
Date: Wed, 21 Oct 2020 15:30:39 +0530
Subject: [PATCH 1/6] added leetcode problems #27

---
 leetcode/cpp/Array/84.cpp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 leetcode/cpp/Array/84.cpp

diff --git a/leetcode/cpp/Array/84.cpp b/leetcode/cpp/Array/84.cpp
new file mode 100644
index 00000000..8adfba47
--- /dev/null
+++ b/leetcode/cpp/Array/84.cpp
@@ -0,0 +1,24 @@
+class Solution {
+public:
+int largestRectangleArea(vector<int> &A) {
+    int res = 0;
+    A.push_back(0);
+
+    stack<int> st;
+
+    for(auto i=0; i<A.size(); i++)
+    {
+        if(st.empty() || A[i] >= A[st.top()])
+            st.push(i);
+        else
+        {
+            int j = st.top();
+            st.pop();
+            res = max(res, A[j]*(st.empty() ? i : i - st.top() - 1));
+            i--;
+        }
+    }
+
+    return res;
+}
+};

From 77167b051cc12e73128e003a0e84b0c350c23164 Mon Sep 17 00:00:00 2001
From: simran2607 <56145342+simran2607@users.noreply.github.com>
Date: Wed, 21 Oct 2020 15:36:09 +0530
Subject: [PATCH 2/6] added leetcode problems #27

---
 leetcode/cpp/Stacks/155.cpp | 49 +++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 leetcode/cpp/Stacks/155.cpp

diff --git a/leetcode/cpp/Stacks/155.cpp b/leetcode/cpp/Stacks/155.cpp
new file mode 100644
index 00000000..d389f30c
--- /dev/null
+++ b/leetcode/cpp/Stacks/155.cpp
@@ -0,0 +1,49 @@
+class MinStack {
+public:
+    /** initialize your data structure here. */
+    MinStack() {
+
+    }
+     stack<int> st;
+    stack<int> min_st;
+    void push(int x) {
+        st.push(x);
+    int val =x;
+   if(min_st.size()>0 && min_st.top()<x)
+   {
+       val =min_st.top();
+   }
+    min_st.push(val);
+    }
+
+    void pop() {
+       if(!st.empty())
+   { st.pop();
+     min_st.pop();
+   }
+    }
+
+    int top() {
+       if(st.empty())
+    return -1;
+    else
+    return st.top();
+
+    }
+
+    int getMin() {
+        if(st.empty())
+    return -1;
+    else
+    return min_st.top();
+    }
+};
+
+/**
+ * Your MinStack object will be instantiated and called as such:
+ * MinStack* obj = new MinStack();
+ * obj->push(x);
+ * obj->pop();
+ * int param_3 = obj->top();
+ * int param_4 = obj->getMin();
+ */

From adc041d9436aefea794a450602999fb77a8a4f88 Mon Sep 17 00:00:00 2001
From: simran2607 <56145342+simran2607@users.noreply.github.com>
Date: Wed, 21 Oct 2020 15:47:47 +0530
Subject: [PATCH 3/6] added leetcode problems #27

---
 leetcode/cpp/Array/31.cpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 leetcode/cpp/Array/31.cpp

diff --git a/leetcode/cpp/Array/31.cpp b/leetcode/cpp/Array/31.cpp
new file mode 100644
index 00000000..a8b3267d
--- /dev/null
+++ b/leetcode/cpp/Array/31.cpp
@@ -0,0 +1,26 @@
+class Solution {
+public:
+    void nextPermutation(vector<int>& A) {
+        int i,j;
+    int n = A.size();
+    for(i = n - 2;i >= 0;i --)
+    {
+        if(A[i] < A[i + 1])
+            break;
+    }
+    if(i == -1)
+    {
+        reverse(A.begin(),A.end());
+        return ;
+    }
+
+    for(j = n - 1;j > i;j --)
+    {
+        if(A[j] > A[i])
+            break;
+    }
+    swap(A[j],A[i]);
+    reverse(A.begin() + i + 1,A.end());
+    return ;
+    }
+};

From 3c5eaae7cfed32297619d5f1112860cf4172a922 Mon Sep 17 00:00:00 2001
From: simran2607 <56145342+simran2607@users.noreply.github.com>
Date: Wed, 21 Oct 2020 16:00:18 +0530
Subject: [PATCH 4/6] added leetcode problems

---
 leetcode/cpp/Two Pointer/16.cpp | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 leetcode/cpp/Two Pointer/16.cpp

diff --git a/leetcode/cpp/Two Pointer/16.cpp b/leetcode/cpp/Two Pointer/16.cpp
new file mode 100644
index 00000000..3c1583d4
--- /dev/null
+++ b/leetcode/cpp/Two Pointer/16.cpp	
@@ -0,0 +1,31 @@
+class Solution {
+public:
+    int threeSumClosest(vector<int>& A, int target) {
+     sort(A.begin(),A.end());
+    int f,s,t;
+    int res=0;
+    int min_diff =INT_MAX;
+    for(f=0;f<A.size()-2;f++)
+    {
+        s= f+1;
+        t=A.size()-1;
+        while(s<t)
+        { int sum= A.at(f) + A.at(s) + A.at(t);
+          int cur = fabs(sum-target);
+          if(cur<min_diff)
+          {
+              min_diff =cur;
+              res =sum;
+          }
+          if(sum>target)
+           t--;
+           else if(sum<target)
+           s++;
+           else
+           return sum;
+
+        }
+    }
+    return res;
+    }
+};

From 55078b4c56c821087787c2768f9c4c067a9b6654 Mon Sep 17 00:00:00 2001
From: simran2607 <56145342+simran2607@users.noreply.github.com>
Date: Wed, 21 Oct 2020 16:00:47 +0530
Subject: [PATCH 5/6] added leetcode problems

---
 16.cpp | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 16.cpp

diff --git a/16.cpp b/16.cpp
new file mode 100644
index 00000000..3c1583d4
--- /dev/null
+++ b/16.cpp
@@ -0,0 +1,31 @@
+class Solution {
+public:
+    int threeSumClosest(vector<int>& A, int target) {
+     sort(A.begin(),A.end());
+    int f,s,t;
+    int res=0;
+    int min_diff =INT_MAX;
+    for(f=0;f<A.size()-2;f++)
+    {
+        s= f+1;
+        t=A.size()-1;
+        while(s<t)
+        { int sum= A.at(f) + A.at(s) + A.at(t);
+          int cur = fabs(sum-target);
+          if(cur<min_diff)
+          {
+              min_diff =cur;
+              res =sum;
+          }
+          if(sum>target)
+           t--;
+           else if(sum<target)
+           s++;
+           else
+           return sum;
+
+        }
+    }
+    return res;
+    }
+};

From 9f3c7d670c23021a4074c1704f321b215c54d57b Mon Sep 17 00:00:00 2001
From: simran2607 <56145342+simran2607@users.noreply.github.com>
Date: Wed, 21 Oct 2020 16:04:07 +0530
Subject: [PATCH 6/6] added leetcode problems #27

---
 leetcode/cpp/Two Pointer/75.cpp | 43 ++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 22 deletions(-)

diff --git a/leetcode/cpp/Two Pointer/75.cpp b/leetcode/cpp/Two Pointer/75.cpp
index 1e5d7dfe..5141004f 100644
--- a/leetcode/cpp/Two Pointer/75.cpp	
+++ b/leetcode/cpp/Two Pointer/75.cpp	
@@ -1,22 +1,21 @@
-class Solution {
-public:
-    void sortColors(vector<int>& nums) {
-        int  low=0,mid=0,high=nums.size()-1;
-        while(mid<=high){
-            
-            if(nums[mid]==0)
-            {
-              swap(nums[low],nums[mid]);
-                low++,mid++;
-            }
-            else if(nums[mid]==1)
-            {
-                mid++;
-            }
-            else{
-                swap(nums[mid],nums[high]);
-                high--;
-            }
-        }
-    }
-};
+class Solution {
+public:
+    void sortColors(vector<int>& A) {
+        int count_0=0,count_1=0,count_2=0;
+    for(int i=0;i<A.size();i++)
+    {
+        if(A[i]==0)
+         count_0++;
+        else if(A[i]==1)
+         count_1++;
+        else if(A[i]==2)
+         count_2++;
+    }
+    for(int i=0;i<count_0;i++)
+      A[i]=0;
+    for(int i=count_0;i<count_0+count_1;i++)
+      A[i]=1;
+    for(int i=count_1+count_0;i<count_0+count_1+count_2;i++)
+      A[i]=2;
+    }
+};