LeetCode-53. Maximum Subarray

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问题描述

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

A subarray is a contiguous part of an array.

Example :

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Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
Output: 6
Explanation: [4,-1,2,1] has the largest sum = 6.

Constraints:

  • 1 <= nums.length <= 105
  • -104 <= nums[i] <= 104

解答

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/*
 * @Description: 53. Maximum Subarray
 * @Author: libk
 * @Github: https://github.com/libk
 */
/**
 * @param {number[]} nums
 * @return {number}
 */
const maxSubArray = function (nums) {
  let pre = 0
  let maxSum = nums[0]
  const maxSubArr = []
  let start = 0
  let end = 0

  for (let i = 0; i < nums.length; i++) {
    if (pre + nums[i] > nums[i]) {
      pre = pre + nums[i]
      if (pre > maxSum) {
        maxSum = pre
        end = i
      }
    } else {
      pre = nums[i]
      if (pre > maxSum) {
        maxSum = pre
        start = i
        end = i
      }
    }
  }
  maxSubArr = nums.slice(start, end + 1)
  console.log(maxSubArr)
  return maxSum
}