Split Array Largest Sum

Description

Given an array nums which consists of non-negative integers and an integer m, you can split the array into m non-empty continuous subarrays.

Write an algorithm to minimize the largest sum among these m subarrays.

 

Example 1:

Input: nums = [7,2,5,10,8], m = 2
Output: 18
Explanation:
There are four ways to split nums into two subarrays.
The best way is to split it into [7,2,5] and [10,8],
where the largest sum among the two subarrays is only 18.

Example 2:

Input: nums = [1,2,3,4,5], m = 2
Output: 9

Example 3:

Input: nums = [1,4,4], m = 3
Output: 4

 

Constraints:

• 1 <= nums.length <= 1000
• 0 <= nums[i] <= 106
• 1 <= m <= min(50, nums.length)

Solution(javascript)

/*
 * @lc app=leetcode id=410 lang=javascript
 *
 * [410] Split Array Largest Sum
 */

// @lc code=start
/**
 * @param {number[]} nums
 * @param {number} m
 * @return {number}
 */
const splitArray = function (nums, m) {
  let left = 0
  let right = 0
  for (const num of nums) {
    left = Math.max(left, num)
    right += num
  }
  while (left <= right) {
    const middle = Math.floor(left + (right - left) / 2)
    let currentSum = 0
    let count = 1
    for (const num of nums) {
      currentSum += num
      if (currentSum > middle) {
        currentSum = num
        count += 1
      }
    }
    // console.log(count)
    if (count < m) {
      right = middle - 1
    } else if (count > m) {
      left = middle + 1
    } else {
      right = middle - 1
    }
  }
  return left
}
// @lc code=end