leetcode-explore-challenge-card-may-leetcoding-challenge-534-week-1-may-1st-may-7th-3316.cpp

// The API isBadVersion is defined for you.
// bool isBadVersion(int version);

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