278-第一个错误的版本.ts

var solution = function(isBadVersion: any) {

    return function(n: number): number {
        if(n === 1) return n

        let left = 1
        let right = n
        while(left < right){
            let mid = Math.floor(left+(right-left)/2)
            if(isBadVersion(mid)){
                right = mid
            }else{
                left = mid + 1
            }
        }    
        return left
    };
};