C. Game on Permutation

合集 - 博弈(8)

1.B. Coin Games2024-05-142.C. Swap Game2024-05-153.A. Jellyfish and Game2024-05-154.P8901 [USACO22DEC] Circular Barn S2024-06-085.D. World is Mine2024-07-026.C. Salyg1n and the MEX Game2024-07-21

7.C. Game on Permutation2024-07-21

8.P10838 『FLA - I』庭中有奇树2024-08-07

收起

原题链接

code

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

void solve()
{
    int n;
    cin>>n;

    vector<int> p(n+4);
    for(int i=1;i<=n;i++) cin>>p[i];


    set<int> lose,win;//lose表示先移动必输的点
    for(int i=1;i<=n;i++)//bob先移动，如果bob不能移动，bob赢，否则bob必须要选择一个小于其的点，如果存在一个先移动必输的点，bob往那里移动，然后bob可以赢
    {
        if(((lose.empty()||*lose.begin()>p[i])&&(win.empty()||*win.begin()>p[i]))||(lose.size()&&*lose.begin()<p[i])) win.insert(p[i]);
        else lose.insert(p[i]);
    }

    cout<<lose.size()<<'\n';//bob先移动，所以bob lose==alice win
}
int main()
{
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    int t=1;
    cin>>t;
    while(t--) solve();
    return 0;
}