John
Time Limit: 5000/1000 MS (Java/Others) Memory Limit: 65535/32768 K (Java/Others)
http://acm.hdu.edu.cn/showproblem.php?pid=1907
Problem Description
Little John is playing very funny game with his younger
brother. There is one big box filled with M&Ms of different colors. At first
John has to eat several M&Ms of the same color. Then his opponent has to
make a turn. And so on. Please note that each player has to eat at least one
M&M during his turn. If John (or his brother) will eat the last M&M from
the box he will be considered as a looser and he will have to buy a new candy
box.
Both of players are using optimal game strategy. John starts first always. You will be given information about M&Ms and your task is to determine a winner of such a beautiful game.
Both of players are using optimal game strategy. John starts first always. You will be given information about M&Ms and your task is to determine a winner of such a beautiful game.
Input
The first line of input will contain a single integer T
– the number of test cases. Next T pairs of lines will describe tests in a
following format. The first line of each test will contain an integer N – the
amount of different M&M colors in a box. Next line will contain N integers
Ai, separated by spaces – amount of M&Ms of i-th
color.
Constraints:
1 <= T <= 474,
1 <= N <= 47,
1 <= Ai <= 4747
Constraints:
1 <= T <= 474,
1 <= N <= 47,
1 <= Ai <= 4747
Output
Output T lines each of them containing information
about game winner. Print “John” if John will win the game or “Brother” in other
case.
Sample Input
2
3
3 5 1
1
1
Sample Output
John
Brother
题意:Nim取石子,取到最后一个的输
若局面异或和为不为0,定义其为S态,否则,定义其为T态
若一堆石子只有1个,定义其为孤独堆,否则,定义其为充裕堆
S0:无充裕堆,异或和不为0
S1:有1个充裕堆,异或和不为0
S2:有>=2个充裕堆,异或和不为0
T0:无充裕堆,异或和为0
T1不存在
T2:有>=2个充裕堆,异或和为0
S0:一定是有奇数个孤独堆,所以必败
T0:一定是有偶数个孤独堆,必胜
S1:若孤独堆个数为奇数,则拿空充裕堆,那么留给对方的是S0态,所以S1必胜
S2:可以转到S1、T2
T2:可以转到S1、S2
若T2转到了S2,则S2有转回了T2
若T2转到了S1,则T2必败
所以S2必胜
#include<cstdio> using namespace std; int main() { int T,n,x,sum,yh; scanf("%d",&T); while(T--) { scanf("%d",&n); sum=yh=0; for(int i=1;i<=n;i++) { scanf("%d",&x); yh^=x; if(x>1) sum++; } if(yh&&!sum) printf("Brother "); else if(!yh&&sum>=2) printf("Brother "); else printf("John "); } }