LeetCode278-第一个错误版本-二分

原图链接

就是个二分，但是要用long long 否则会爆

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

class Solution {
public:
    int firstBadVersion(int n) {
        long long l = 1, r = n;
        while(l < r){
            long long mid = l + r >> 1;
            if(isBadVersion(mid))   r = mid;
            else l = mid + 1;
        }
        return r;
    }
};