C# 代码

public class Solution {
    public int PivotIndex(int[] nums) {
        // 提示nums.Length >= 1 如果为空需要返回-1
        int total = 0;
        foreach (int num in nums)
        {
            total += num;
        }

        int sum = 0;
        for (int i = 0; i < nums.Length; i++)
        {
            sum += nums[i];
            if (sum + sum - nums[i] == total)
            {
                return i;
            }
        }

        return -1;
    }
}