面试题 42. 连续子数组的最大和

输入: nums = [-2,1,-3,4,-1,2,1,-5,4]
输出: 6
解释: 连续子数组 [4,-1,2,1] 的和最大，为 6。

class Solution:
    def maxSubArray(self, nums: List[int]) -> int:
        n = len(nums)
        res = f = nums[0]
        for i in range(1, n):
            f = nums[i] + max(f, 0)
            res = max(res, f)
        return res

class Solution {
    public int maxSubArray(int[] nums) {
        int res = nums[0], f = nums[0];
        for (int i = 1, n = nums.length; i < n; ++i) {
            f = nums[i] + Math.max(f, 0);
            res = Math.max(res, f);
        }
        return res;
    }
}

/**
 * @param {number[]} nums
 * @return {number}
 */
var maxSubArray = function (nums) {
  let res = nums[0];
  let f = nums[0];
  for (let i = 1; i < nums.length; ++i) {
    f = Math.max(f, 0) + nums[i];
    res = Math.max(res, f);
  }
  return res;
};

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int res = nums[0], f = nums[0];
        for (int i = 1; i < nums.size(); ++i) {
            f = max(f, 0) + nums[i];
            res = max(res, f);
        }
        return res;
    }
};

func maxSubArray(nums []int) int {
    f, res := nums[0], nums[0]
    for i := 1; i < len(nums); i++ {
        if f > 0 {
            f += nums[i]
        } else {
            f = nums[i]
        }
        if f > res {
            res = f
        }
    }
    return res
}