class Solution {
public int getNumberSameAsIndex(int[] nums) {
int left = 0;
int right = nums.length - 1;
while(left <= right){
int mid = left + (right - left) / 2;
if(nums[mid] == mid){
return mid;
}else if(nums[mid] < mid){
left = mid + 1;
}else if(nums[mid] > mid){
right = mid - 1;
}
}
return -1;
}

}