First Bad Version
给一个API, 找到一个返回false的数. 这个就是二分查找.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 |
/* 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 i = 1; int j = n; while(i<=j) { int m = i + (j-i) / 2; if(isBadVersion(m)) j = m - 1; else i = m + 1; } return i; } } |