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.思路就是二分查找法。
public int guessNumber(int n) { int low = 1, high = n; while (low <= high) { int mid = (high - low) / 2 + low, val = guess(mid); if (val == 0) return mid; else if (val == -1) high = mid - 1; else low = mid + 1; } return -1; }