博弈专题

CodeForces - 549C

剩下的人数之和为奇数时先手胜，否则后手胜。

考虑最后一步

#include <bits/stdc++.h>
using namespace std;

int main(){
    //ios_base::sync_with_stdio(0);
    int n, k;
    while(cin>>n>>k){
        int cnt = 0;
        int x;
        long long sum = 0;
        for(int i = 0;  i < n; i++){
            scanf("%d", &x);
            sum = sum + x;
            if(x & 1) cnt++;
        }
        int ok = 1;
        if(n == k){
            if(sum & 1) ok = 1;
            else ok = 0;
        }else{
            int m = n - k, op = m / 2;
            if(m & 1) { // 先手最后拿
                if(k & 1){
                    if(op >= cnt) ok = 0;
                    else ok = 1;
                }else{
                    if(op >= cnt || op >= (n - cnt)) ok = 0;
                    else ok = 1;
                }
            }else {
                if(k & 1){
                    if(op >= (n - cnt)) ok = 1;
                    else  ok = 0;
                }else{
                    ok = 0;
                }
            }
        }
        if(ok) cout<<"Stannis
";
        else cout<<"Daenerys
";
    }
}

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