HDU 2176 (Nim博弈 先手取胜方案) 取(m堆)石子游戏

 1 #include <cstdio>
 2 
 3 const int maxn = 200000 + 10;
 4 int a[maxn];
 5 
 6 int main()
 7 {
 8     //freopen("in.txt", "r", stdin);
 9 
10     int m;
11     while(scanf("%d", &m) == 1 && m)
12     {
13         int s = 0;
14         for(int i = 0; i < m; i++) { scanf("%d", &a[i]); s ^= a[i]; }
15         if(!s) { puts("No"); continue; }
16         puts("Yes");
17         int k = -1;
18         int t = s;
19         while(s) { s >>= 1; k++; }
20         for(int i = 0; i < m; i++) if(a[i] & (1 << k)) printf("%d %d\n", a[i], a[i] ^ t);
21     }
22 
23     return 0;
24 }