278. First Bad Version

题目

278. First Bad Version

解题思路

很明显就是二分搜索，但是被溢出坑了很久一直超时qaq
超时的解决方法：

• 类型转换：long long int mid = ((long long int)left + (long long int)right) / 2;

• 防溢出代码：int mid = left + (right - left) / 2;

（Binary search algorithm）

具体代码

// Forward declaration of isBadVersion API.bool isBadVersion(int version);class Solution {public:    int binary_search(int left, int right) {        while (left < right) {            long long int mid = ((long long int)left + (long long int)right) / 2;            if (isBadVersion(mid)) {                right = mid;            }            else {                left = mid + 1;            }        }        return left;    }    int firstBadVersion(int n) {        return binary_search(1, n);    }};