// @Title: 第一个错误的版本 (First Bad Version)
// @Author: qisiii
// @Date: 2022-02-26 11:56:41
// @Runtime: 20 ms
// @Memory: 38.1 MB
// @comment: 
// @flag: 
/* The isBadVersion API is defined in the parent class VersionControl.
      boolean isBadVersion(int version); */

public class Solution extends VersionControl {
    public int firstBadVersion(int n) {
        int left=1,right=n;
        while(left<=right){
            int mid=left+(right-left)/2;
        if(isBadVersion(mid)){
            right=mid-1;
        }else{
            left=mid+1;
        }
        }
        return left;
    }
}