Leetcode: find the center index of the array

Leetcode: find the center index in the array

Overview

• The center index means that the sum of all the values ​​on the left of the center index is equal to the sum of all the values ​​on the right of the center index. If there is no such index, it returns -1.
• E.g:
  • Target array: [1,2,3,5,6]
  • Output: 3 (this means that the index is not a value, that is, num[3])
  • Explanation: The value of 5 on the left is added to 6 to equal the value of 6 on the right.

C language problem solution

/*
    @nums:数组
    @numsSize：数组长度
*/
int pivotIndex(int* nums,int numsSize){
	int sum=0,i=0,left=0;
    // 计算出数组的总和
    for(i=0;i<numsSize;i++){
        sum+=nums[i];
    };
    //寻找中心索引
    for(i=0;i<numsSize;i++){
        //若左边和右边的和相同
        if(left == sum - nums[i] - left){
            return i;
        }
        //否则就加入left
        left += nums[i];  
    };
    //无返回值，说明无中心索引
    return -1;
}