找到数组平衡索引使得左半部分等于右半部分

/*
find the balance index of an array where balanced index i is defined as the one whose left sum is equal to the right sum of the index . 
*/

#include <cstdio>

int findBalanceIdx(int* a, int n)
{
	int sum = 0;
	for(int i = 0; i < n; i++)
		sum += a[i];

	int leftSum = 0;

	for(int i = 0; i < n; i++)
	{
		sum -= a[i];

		if(leftSum == sum)
			return i;

		leftSum += a[i];
	}

	return -1;
};

int main()
{
	int a[] = {-7, 1, 5, 2, -4, 3, 0};

	int res = findBalanceIdx(a, 7);

	return 0;
}