LeetCode-in-All
53. Maximum Subarray
Medium
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 1:
Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
Output: 6
Explanation: [4,-1,2,1] has the largest sum = 6.
Example 2:
Input: nums = [1]
Output: 1
Example 3:
Input: nums = [5,4,-1,7,8]
Output: 23
Constraints:
1 <= nums.length <= 105-104 <= nums[i] <= 104
Follow up: If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.
Solution
impl Solution {
pub fn max_sub_array(nums: Vec<i32>) -> i32 {
let mut maxi = i32::MIN;
let mut sum = 0;
for &num in nums.iter() {
// calculating sub-array sum
sum += num;
maxi = maxi.max(sum);
// if the sum is negative, reset it to 0
if sum < 0 {
sum = 0;
}
}
maxi
}
}