http://lintcode.com/en/problem/first-bad-version/
/**
* public class VersionControl {
* public static boolean isBadVersion(int k);
* }
* you can use VersionControl.isBadVersion(k) to judge wether
* the kth code version is bad or not.
*/
class Solution {
/**
* @param n: An integers.
* @return: An integer which is the first bad version.
*/
public int findFirstBadVersion(int n) {
// write your code here
int low = 1;
int high = n;
while (low < high)
{
int mid = low + (high - low) / 2;
if (VersionControl.isBadVersion(mid))
{
high = mid;
}
else
{
low = mid + 1;
}
}
if (VersionControl.isBadVersion(low))
return low;
else
return -1; // Not found.
}
}