Package g0201_0300.s0278_first_bad_version

Class Solution

java.lang.Object
g0201_0300.s0278_first_bad_version.VersionControl
g0201_0300.s0278_first_bad_version.Solution
public class Solution extends VersionControl
278 - First Bad Version.

Easy

You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the previous version, all the versions after a bad version are also bad.

Suppose you have n versions [1, 2, ..., n] and you want to find out the first bad one, which causes all the following ones to be bad.

You are given an API bool isBadVersion(version) which returns whether version is bad. Implement a function to find the first bad version. You should minimize the number of calls to the API.

Example 1:

Input: n = 5, bad = 4

Output: 4

Explanation:

 call isBadVersion(3) -> false
 call isBadVersion(5) -> true
 call isBadVersion(4) -> true
 Then 4 is the first bad version.

Example 2:

Input: n = 1, bad = 1

Output: 1

Constraints:

  • 1 <= bad <= n <= 231 - 1

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution(int bad)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    firstBadVersion(int n)
     

    Methods inherited from class g0201_0300.s0278_first_bad_version.VersionControl

    isBadVersion

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution(int bad)

  • Method Details

    • firstBadVersion

      public int firstBadVersion(int n)