1167-MinimumCostToConnectSticks.ts

// ---------------- LEETCODE TASK DESCRIPTION ----------------- //
// --------- 1167 - Minimum Cost to Connect Sticks ------------ //

/* You have some number of sticks with positive integer lengths. These lengths are given as an array sticks, where sticks[i] is the length of the ith stick.

You can connect any two sticks of lengths x and y into one stick by paying a cost of x + y. You must connect all the sticks until there is only one stick remaining.

Return the minimum cost of connecting all the given sticks into one stick in this way.

 

Example 1:

Input: sticks = [2,4,3]
Output: 14
Explanation: You start with sticks = [2,4,3].
1. Combine sticks 2 and 3 for a cost of 2 + 3 = 5. Now you have sticks = [5,4].
2. Combine sticks 5 and 4 for a cost of 5 + 4 = 9. Now you have sticks = [9].
There is only one stick left, so you are done. The total cost is 5 + 9 = 14.
Example 2:

Input: sticks = [1,8,3,5]
Output: 30
Explanation: You start with sticks = [1,8,3,5].
1. Combine sticks 1 and 3 for a cost of 1 + 3 = 4. Now you have sticks = [4,8,5].
2. Combine sticks 4 and 5 for a cost of 4 + 5 = 9. Now you have sticks = [9,8].
3. Combine sticks 9 and 8 for a cost of 9 + 8 = 17. Now you have sticks = [17].
There is only one stick left, so you are done. The total cost is 4 + 9 + 17 = 30.
Example 3:

Input: sticks = [5]
Output: 0
Explanation: There is only one stick, so you don't need to do anything. The total cost is 0.
 */

// ------------------------ SOLUTION -------------------------- //

// While there are more than one stick:
// 1. Take two smallest sticks
// 2. Connect them
// 3. Add the cost to the result
// 4. Insert the connected stick back to the array
// 5. Repeat until there is only one stick

// Time complexity: O(n log n)
// Space complexity: O(n)

const connectSticks = (sticks: number[]): number => {
  sticks.sort((a, b) => a - b); 

  let result = 0;

  while (sticks.length > 1) {
      const first = sticks.shift() as number;
      const second = sticks.shift() as number;

      const temp = first + second;
      result += temp;
      let insertIndex = 0;
      while (insertIndex < sticks.length && sticks[insertIndex] < temp) {
          insertIndex++;
      }

      sticks.splice(insertIndex, 0, temp);
  }

  return result;
}


// --------------------------- LOGS --------------------------- //

console.log(connectSticks([2,4,3]))
console.log(connectSticks([1,8,3,5]))
console.log(connectSticks([5]))

// ----------------------- CLI COMMAND ------------------------ //

//run ts-node 1167-MinimumCostToConnectSticks.ts