有趣的新手练习题

Posted 2021-05-07 nervendnig

hdu 1079 记忆化搜索

#include<bits/stdc++.h>
#define rep(ii,a,b) for(int ii=a;ii<=b;++ii)
#define IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
using namespace std;//head
int casn,n,m,k,kasn;
int vis[2100][15][40];
int day[2][13]={{0,31,28,31,30,31,30,31,31,30,31,30,31},
                {0,31,29,31,30,31,30,31,31,30,31,30,31}};
int dfs(int y,int m,int d){
  if(~vis[y][m][d]) return vis[y][m][d];
  int flag=0,r=(y%4==0&&y%100!=0)||(y%400==0);
  if(m<12&&day[r][m+1]>=d) flag|=!dfs(y,m+1,d);
  if(!flag){
    if(d==day[r][m]){
      if(m==12)flag|=!dfs(y+1,1,1);
      else flag|=!dfs(y,m+1,1);
    }else flag|=!dfs(y,m,d+1);
  }
  return vis[y][m][d]=flag;
}
int main() {IO;
  cin>>casn;
  memset(vis,-1,sizeof vis);
  rep(i,2001,2010)rep(j,1,12)rep(k,1,31){
    if(i>2001) vis[i][j][k]=1;
    else if(j>11) vis[i][j][k]=1;
    else if(j==11&&k>4) vis[i][j][k]=1;
  }
  vis[2001][11][4]=0;
  while(casn--){
    int y,m,d;cin>>y>>m>>d;
    if(dfs(y,m,d))cout<<"YES
";
    else cout<<"NO
";
  }
}

 gym100500A dfs+回溯

#include<bits/stdc++.h>
#define ll long long
#define rep(ii,a,b) for(int ii=a;ii<=b;++ii)
#define per(ii,a,b) for(int ii=b;ii>=a;--ii)
#define IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
using namespace std;//head
const int maxn=30+10,maxm=2e6+10;
int casn,n,m,k;
int s1[maxn][maxn][2];
int cnt[2];
bool dfs(int now,int p){
  if(cnt[p]==0) return false;
  bool flag=false;
  rep(i,0,25){
    if(s1[now][i][p]){
      s1[now][i][p]--;
      cnt[p]--;
      flag|=!dfs(i,1-p);
      s1[now][i][p]++;
      cnt[p]++;
    }
  }
  return flag;
}
int main() {IO;
  cin>>casn;
  int kase=0;
  while(casn--){
    cin>>n;
    string s;
    memset(s1,0,sizeof s1);
    getline(cin,s);
    rep(i,1,n){
      getline(cin,s);
      int a=s[0]-‘a‘;
      int b=s.back()-‘a‘;
      s1[a][b][0]++;
    }
    cin>>m;
    getline(cin,s);
    rep(i,1,m){
      getline(cin,s);
      int a=s[0]-‘a‘;
      int b=s.back()-‘a‘;
      s1[a][b][1]++;
    }
    cnt[0]=n;
    cnt[1]=m;
    int flag=0;
    rep(i,0,25){
      rep(j,0,25){
        if(s1[i][j][0]){
          s1[i][j][0]--;
          cnt[0]--;
          flag|=!dfs(j,1);
          s1[i][j][0]++;
          cnt[0]++;
        }
      }
    }
    cout<<"Game "<<++kase<<": player"<<2-flag<<‘
‘;
  }  
}