278. First Bad Version

https://leetcode.com/problems/first-bad-version/

JavaScript

/**
 * Definition for isBadVersion()
 * 
 * @param {integer} version number
 * @return {boolean} whether the version is bad
 * isBadVersion = function(version) {
 *     ...
 * };
 */

/**
 * @param {function} isBadVersion()
 * @return {function}
 */
var solution = function(isBadVersion) {
    /**
     * @param {integer} n Total versions
     * @return {integer} The first bad version
     */
    return function(n) {
        return check(1, n);

        function check(min, max) {
            if (min === max) {
                return min;
            }

            var mid = (min + max) / 2 >> 0;
            return isBadVersion(mid) ? check(min, mid) : check(mid + 1, max);
        }
    };
};

Python

# The isBadVersion API is already defined for you.
# @param version, an integer
# @return a bool
# def isBadVersion(version):


class Solution(object):
    def firstBadVersion(self, n):
        """
        :type n: int
        :rtype: int
        """
        left, right = 1, n
        while left < right:
            mid = (left + right) // 2
            if isBadVersion(mid):
                right = mid
            else:
                left = mid + 1
        return left