Minimum Subarray

Given an array of integers, find the subarray with smallest sum.

Return the sum of the subarray.

 Notice

The subarray should contain one integer at least.

Example

For [1, -1, -2, 1], return -3.

Analyse: Greedy. If the previous sum is larger than 0, then we shouldn't combine the current value with the previous sum. Otherwise, we should combine them together. Every time we deal with a value, we should update the minSum. 

Runtime: 36ms

class Solution {
public:
    /**
     * @param nums: a list of integers
     * @return: A integer denote the sum of minimum subarray
     */
    int minSubArray(vector<int> nums) {
        // write your code here
        
        // greedy
        if (nums.empty()) return 0;
        
        int minSum = INT_MAX, tempSum = 0;
        for (int i = 0; i < nums.size(); i++) {
            if (tempSum > 0) 
                tempSum = nums[i];
            else 
                tempSum += nums[i];
                
            minSum = min(minSum, tempSum);
        }
        return minSum;
    }
};