53. Max subarray

#include <limits.h>

int maxSubArray(int *nums, int numsSize) {
  int sum = 0;
  int mx = INT_MIN;

  for (int i = 0; i < numsSize; i++) {
    sum += nums[i];
    if (sum > mx)
      mx = sum;
    if (sum < 0)
      sum = 0; // a negative prefix only lowers what follows
  }

  return mx;
}

#include <algorithm>
#include <climits>
#include <vector>

using namespace std;

class Solution {
public:
  int maxSubArray(vector<int> &nums) {
    int sum = 0;
    int mx = INT_MIN;

    for (int i = 0; i < nums.size(); i++) {
      sum += nums[i];
      mx = max(sum, mx);
      if (sum < 0)
        sum = 0; // a negative prefix only lowers what follows
    }

    return mx;
  }
};

package greedy

import "math"

func maxSubArray(nums []int) int {
    sum := 0
    mx := math.MinInt

    for _, n := range nums {
        sum += n
        mx = max(sum, mx)
        if sum < 0 {
            sum = 0 // a negative prefix only lowers what follows
        }
    }

    return mx
}

class Solution {
    public int maxSubArray(int[] nums) {
        int sum = 0;
        int mx = Integer.MIN_VALUE;

        for (int n : nums) {
            sum += n;
            mx = Math.max(sum, mx);
            if (sum < 0)
                sum = 0; // a negative prefix only lowers what follows
        }

        return mx;
    }
}

/**
 * @param {number[]} nums
 * @return {number}
 */
var maxSubArray = function (nums) {
  let sum = 0;
  let mx = -Infinity;

  for (const n of nums) {
    sum += n;
    mx = Math.max(sum, mx);
    if (sum < 0) sum = 0; // a negative prefix only lowers what follows
  }

  return mx;
};

from typing import List


class Solution:
    def maxSubArray(self, nums: List[int]) -> int:
        total = 0
        mx = float("-inf")

        for n in nums:
            total += n
            mx = max(total, mx)
            if total < 0:
                total = 0  # a negative prefix only lowers what follows

        return mx

impl Solution {
    pub fn max_sub_array(nums: Vec<i32>) -> i32 {
        let mut sum = 0;
        let mut mx = i32::MIN;

        for n in nums {
            sum += n;
            mx = mx.max(sum);
            if sum < 0 {
                sum = 0; // a negative prefix only lowers what follows
            }
        }

        mx
    }
}