We are playing the Guess Game. The game is as follows:
I pick a number from 1 to n. You have to guess which number I picked.
Every time you guess wrong, I'll tell you whether the number is higher or lower.
You call a pre-defined API guess(int num) which returns 3 possible results (-1, 1, or 0):
-1 : My number is lower
1 : My number is higher
0 : Congrats! You got it!
Example:
n = 10, I pick 6.
Return 6.
Solution：Binary Search
Time Complexity: O(logN) Space Complexity: O(1)
Solution Code：
public class Solution extends GuessGame {
public int guessNumber(int n) {
int start = 1, end = n;
while(start < end) {
int mid = start + (end - start) / 2;
if(guess(mid) == 0) {
return mid;
} else if(guess(mid) == 1) {
start = mid + 1;
} else {
end = mid;
}
}
return start;
}
}
