HDU

To begin or not to begin

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 1061    Accepted Submission(s): 689

Problem Description

A box contains black balls and a single red ball. Alice and Bob draw balls from this box without replacement, alternating after each draws until the red ball is drawn. The game is won by the player who happens to draw the single red ball. Bob is a gentleman and offers Alice the choice of whether she wants to start or not. Alice has a hunch that she might be better off if she starts; after all, she might succeed in the first draw. On the other hand, if her first draw yields a black ball, then Bob’s chances to draw the red ball in his first draw are increased, because then one black ball is already removed from the box. How should Alice decide in order to maximize her probability of winning? Help Alice with decision.

 

Input

Multiple test cases (number of test cases≤50), process till end of input.
For each case, a positive integer k (1≤k≤10^5) is given on a single line.

 

Output

For each case, output:
1, if the player who starts drawing has an advantage
2, if the player who starts drawing has a disadvantage
0, if Alice's and Bob's chances are equal, no matter who starts drawing
on a single line.

 

Sample Input

12

 

Sample Output

01

 

这尼玛K是个什么玩意儿，看了好一会儿才发现是黑球个数。。。刚开始以为是所有球的个数结果思路完全跑偏。

简单的概率计算，最后发现当k是奇数时，先手后手获胜概率是相同的，当k是偶数时，先手获胜的几率大些。

#include<stdio.h>int main(){    int k;    while(scanf("%d",&k)!=EOF)    {        if(k%2==0)            printf("%d\n",1);        else            printf("%d\n",0);    }}