AcWing 893. 集合-Nim游戏

Posted 2020-11-22 qingyuyyyyy

//只能拿某些特定个数的石子
#include <cstring>
#include <iostream>
#include <algorithm>
#include <unordered_set>
using namespace std;
const int N = 110, M = 10010;
int n, m;
int s[N], f[M];
int sg(int x) {
    if (f[x] != -1) return f[x];
    unordered_set<int> S;
    for (int i = 0; i < m; i ++ ) {
        int sum = s[i];
        if (x >= sum) S.insert(sg(x - sum));
    }
    for (int i = 0; ; i ++ )
        if (!S.count(i))
            return f[x] = i;
}
int main() {
    cin >> m;
    for (int i = 0; i < m; i ++ ) cin >> s[i];
    cin >> n;
    memset(f, -1, sizeof f);
    int res = 0;
    for (int i = 0; i < n; i ++ ) {
        int x;
        cin >> x;
        res ^= sg(x);
    }
    if (res) puts("Yes");
    else puts("No");
    return 0;
}