组合博弈1536-S-Nim

Arthur and his sister Caroll have been playing a game called Nim for some time now. Nim is played as follows:


  The starting position has a number of heaps, all containing some, not necessarily equal, number of beads.

  The players take turns chosing a heap and removing a positive number of beads from it.

  The first player not able to make a move, loses.


Arthur and Caroll really enjoyed playing this simple game until they recently learned an easy way to always be able to find the best move:


  Xor the number of beads in the heaps in the current position (i.e. if we have 2, 4 and 7 the xor-sum will be 1 as 2 xor 4 xor 7 = 1).

  If the xor-sum is 0, too bad, you will lose.

  Otherwise, move such that the xor-sum becomes 0. This is always possible.


It is quite easy to convince oneself that this works. Consider these facts:

  The player that takes the last bead wins.

  After the winning player's last move the xor-sum will be 0.

  The xor-sum will change after every move.


Which means that if you make sure that the xor-sum always is 0 when you have made your move, your opponent will never be able to win, and, thus, you will win.

Understandibly it is no fun to play a game when both players know how to play perfectly (ignorance is bliss). Fourtunately, Arthur and Caroll soon came up with a similar game, S-Nim, that seemed to solve this problem. Each player is now only allowed to remove a number of beads in some predefined set S, e.g. if we have S =(2, 5) each player is only allowed to remove 2 or 5 beads. Now it is not always possible to make the xor-sum 0 and, thus, the strategy above is useless. Or is it?

your job is to write a program that determines if a position of S-Nim is a losing or a winning position. A position is a winning position if there is at least one move to a losing position. A position is a losing position if there are no moves to a losing position. This means, as expected, that a position with no legal moves is a losing position.
 

Input
Input consists of a number of test cases. For each test case: The first line contains a number k (0 < k ≤ 100 describing the size of S, followed by k numbers si (0 < si ≤ 10000) describing S. The second line contains a number m (0 < m ≤ 100) describing the number of positions to evaluate. The next m lines each contain a number l (0 < l ≤ 100) describing the number of heaps and l numbers hi (0 ≤ hi ≤ 10000) describing the number of beads in the heaps. The last test case is followed by a 0 on a line of its own.
 

Output
For each position: If the described position is a winning position print a 'W'.If the described position is a losing position print an 'L'. Print a newline after each test case.
 

Sample Input
2 2 5 
2 5 12 
3 2 4 7 
4 2 3 7 12 
5 1 2 3 4 5 
2 5 12 
3 2 4 7 
4 2 3 7 12 
0
Sample Output
LWW 
WWL
//还是SG值套模版函数就好了;
#include
#include
#include
using namespace std;
int k,ki[101];
int sg[10001];
int mex(int n)
{
    int i,temp,judge[101] = {0};
    for(i = 0;i < k;i++)
    {
          temp = n - ki[i];
          if(temp < 0)
                   break;
          if(sg[temp] == -1)
                   sg[temp] = mex(temp);
          judge[sg[temp]] = 1;
    }
    for(i = 0;;i++)
            if(judge[i] == 0)
                 return i;
}
int main()
{
    int i,j,l,m,hi;
    while(cin >> k && k)
    {
            string s;
            for(i = 0;i < k;i++)
                  cin >> ki[i];
            sort(ki,ki+k);
            cin >> m;
           memset(sg,-1,sizeof(sg));
            while(m-- && cin >> l)
            {
                      int s_g = 0;
                      for(i = 0;i < l;i++)
                      {
                            cin >> hi;
                            s_g ^= mex(hi);
                      }
                      if(s_g == 0)
                          s += "L";
                      else
                          s += "W";
            }
            cout << s << endl;
    }
    return 0;
}

原文地址:https://www.cnblogs.com/kuroko-ghh/p/9363387.html