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. 一个判断大小的问题，可以用折半查找的方法，难点在于数据可能会超出限制 /* The guess API is defined in the parent class GuessGame. @param num, your guess @return -1 if my number is lower, 1 if my number is higher, otherwise return 0 int guess(int num); */ public class Solution extends GuessGame { public int guessNumber(int n) { int i=1,j=n; while(i<=j) { int mid=i+(j-i)/2; int result=guess(mid); if(result==0)return mid; else if(result<0){ j=mid; } else{ i=mid+1; } } return 0; } }所以在这里用 mid=i+(j-i)/2;而不用mid=（i+j-1）/2；这里极有可能会超出限制，同理如果数字过大也会影响速度！
