pivot index
class Solution {
public int pivotIndex(int[] nums) {
int totalSum = 0;
for (int i = 0; i < nums.length; i++) {
totalSum += nums[i];
}
int leftSum = 0;
for (int i = 0; i < nums.length; i++) {
int rightSum = totalSum - leftSum - nums[i];
if (leftSum == rightSum) {
return i;
}
leftSum += nums[i];
}
return -1; // No pivot index found
}
}