题目地址

https://leetcode.cn/problems/find-pivot-index/description/

题目描述

代码

  class Solution {
    public int pivotIndex(int[] nums) {
        int total = Arrays.stream(nums).sum();

        //前缀和
        int prefixSum =0;
        int len = nums.length;
        for(int i =0;i<len;i++){
            if (i-1>=0){
                prefixSum+=nums[i-1];
            }
            //当前元素的后缀和 = total-nums[i]-prefixSum
            if((total-nums[i]-prefixSum)==prefixSum){
                return i;
            }
        }

        return -1;

    }
}