724. Find Pivot Index

Given an array of integers nums, write a method that returns the "pivot" index of this array.

We define the pivot index as the index where the sum of the numbers to the left of the index is equal to the sum of the numbers to the right of the index.

If no such index exists, we should return -1. If there are multiple pivot indexes, you should return the left-most pivot index.

Example 1:

Input: 
nums = [1, 7, 3, 6, 5, 6]
Output: 3
Explanation: 
The sum of the numbers to the left of index 3 (nums[3] = 6) is equal to the sum of numbers to the right of index 3.
Also, 3 is the first index where this occurs.

Example 2:

Input: 
nums = [1, 2, 3]
Output: -1
Explanation: 
There is no index that satisfies the conditions in the problem statement.




　　水题，大意是给一个int数组，找出这样一个pivot：pivot左边的每个元素相加之和等于pivot右边每个元素相加之和。暴力枚举。

class Solution {
    public int pivotIndex(int[] nums) {
        int len  = nums.length;

        for(int i = 0; i<len; i++) {
            int left = i-1;
            int right = i+1;
            int suml = 0;
            int sumr = 0;
            while(left>=0) {
                suml += nums[left];
                left--;
            }
            while(right<len) {
                sumr += nums[right];
                right++;
            }
            if(suml == sumr) {
                return i;
            }
        }
        return -1;
    }
}