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Minimum Subarray

Minimum Subarray

题目地址

题目描述

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

代码

Apporach #1

minSub = Math.min(minSub, sum - maxSum);
public class Solution {
public int minSubArray(ArrayList<Integer> nums) {
if (nums == null || nums.isEmpty()) return -1;
int sum = 0, maxSum = 0, minSub = Integer.MAX_VALUE;
for (int num : nums) {
maxSum = Math.max(maxSum, sum);
sum += num;
minSub = Math.min(minSub, sum - maxSum);
}
​
return minSub;
}
}

Approach #2 Multiply the array by negative 1, and then maximize it

public class Solution {
public int minSubArray(ArrayList<Integer> nums) {
if (nums == null || nums.isEmpty()) return -1;
int[] copys = new int[nums.size()];
for (int i = 0; i < nums.size(); i++){
copys[i] = -1 * nums[i];
}
​
int sum = 0, maxSum = Integer.MIN_VALUE;
for (int num : copys){
sum = Math.max(sum, 0);
sum += num;
maxSum = Math.max(maxSum, sum);
}
​
return maxSum * -1;
}
}