class Solution {
    public int pivotIndex(int[] nums) {
        int sum = 0, leftSum = 0;
        
        for(int num: nums) 
            sum += num;
        
    
        for(int i=0; i<nums.length; i++)
        {
            if(leftSum == sum - leftSum - nums[i])
                return i;
            leftSum += nums[i];
        }
        return -1;
    }
}