acwing 893 NIM 游戏（sg函数 + 记忆化搜索）

#include <iostream>// 记忆化搜索
#include <unordered_set>
#include <cstring>

using namespace std;

const int N = 110, M = 10010;

int n, m, f[M], res, s[N];

int sg(int x)
{
    if(f[x] != -1) return f[x];
    
    unordered_set<int> S;
    
    for(int i = 0; i < n; i ++)
    {
        if(x - s[i] >= 0) S.insert(sg(x - s[i]));
    }
    
    for(int i = 0; ; i ++)
    {
        if(S.count(i) == 0) return f[x] = i;
    }
}


int main()
{
    cin >> n;
    
    memset(f, -1, sizeof f);
    
    for(int i = 0; i < n ; i ++) scanf("%d", s + i);
    
    cin >> m;
    
    for(int i = 0; i < m ; i ++)
    {
        int p; scanf("%d", &p);
        p = sg(p);
        res ^= p;
    }
    
    if(res != 0) cout << "Yes" << endl;
    else  cout << "No" << endl;
    
    
    
    return 0;
}

#include <iostream>
#include <unordered_set>
#include <algorithm>

using namespace std;

const int N = 110, M = 10010;

int a[N], sg[M], n, m;





int SG (int x)
{
    if(x == 0) return 0;
    unordered_set<int> S;
    for(int i = 0; i < n ; i ++)
    {
        if(x - a[i] >= 0) S.insert(sg[x - a[i]]);
    }
    for(int i = 0; ;i ++)
    {
        if(S.count(i) == 0) return i; 
    }
    
    
}
int main()
{
    cin >> n;
    
    for(int i = 0; i < n ; i ++)  scanf("%d", a + i);
    
    
    
    for(int i = 0; i <= M; i ++)
    {
        sg[i] = SG(i);
        //cout << i << " " << sg[i] << "\n";
    }
    
    cin >> m;
    int res = 0;
    for(int i = 0; i < m ;i ++) 
    {
        int a; cin >> a;
        
        res ^= sg[a];
        
    }
    if(res) cout << "Yes" << endl;
    
    else cout << "No" << endl;
    
    
    return 0;
}