标签：other .com arc pos which leetcode ram number search
原题链接在这里：https://leetcode.com/problems/guess-number-higher-or-lower/
题目：
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.
题解：
Binary Search, guess mid为0则return mid. guess mid为-1, 就在左半面继续猜. guess mid 为1, 就在右半面继续猜.
Time Complexity: O(logn). Space: O(1).
AC Java:
1 /* The guess API is defined in the parent class GuessGame. 2 @param num, your guess 3 @return -1 if my number is lower, 1 if my number is higher, otherwise return 0 4 int guess(int num); */ 5 6 public class Solution extends GuessGame { 7 public int guessNumber(int n) { 8 int l = 1; 9 int r = n; 10 while(l <= r){ 11 int mid = l + (r-l)/2; 12 int result = guess(mid); 13 if(result < 0){ 14 r = mid-1; 15 }else if(result > 0){ 16 l = mid+1; 17 }else{ 18 return mid; 19 } 20 } 21 return -1; 22 } 23 }
LeetCode Guess Number Higher or Lower
标签：other .com arc pos which leetcode ram number search
原文地址：http://www.cnblogs.com/Dylan-Java-NYC/p/6351273.html
