1064. Fixed Point

https://leetcode.com/problems/fixed-point/

Python

class Solution:
    def fixedPoint(self, arr: List[int]) -> int:
        l, r = 0, len(arr)-1

        result = -1
        while l <= r:
            pivot = (l+r) // 2

            if arr[pivot] == pivot:
                result = pivot
                r = pivot - 1
            elif arr[pivot] < pivot:
                l = pivot + 1
            else:
                r = pivot - 1
        return result

Go

func fixedPoint(arr []int) int {
    l, r := 0, len(arr)-1

    result := -1
    for l <= r {
        pivot := (l+r) / 2
        if (arr[pivot] == pivot) {
            result = pivot
            r = pivot - 1
        } else if (arr[pivot] < pivot) {
            l = pivot + 1
        } else {
            r = pivot - 1
        }
    }
    return result
}