leetcode278

/* The isBadVersion API is defined in the parent class VersionControl.
      bool IsBadVersion(int version); */

public class Solution : VersionControl {
    public int FirstBadVersion(int n) {
        var start = 1;
            var end = n;
            while (start < end)
            {
                var mid = start + (end - start) / 2;
                if (!IsBadVersion(mid))
                {
                    start = mid + 1;
                }
                else
                {
                    end = mid;
                }                
            }
            return start;
    }
}

https://leetcode.com/problems/first-bad-version/#/description

 

Java版本：

/* 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 low = 0;
        int high = n;
        while(low < high){
            int mid = low + (high - low) / 2;
            boolean result = isBadVersion(mid);
            if(result){
                high = mid;
            }else{
                low = mid + 1;
            }
        }
        return low;
    }
}