AtCoder Beginner Contest 263

A - Full House

シミュレートします。

C++

#include <bits/stdc++.h>
 
#define rep(i,n) for(int i=0; i<(n); ++i)
#define repx(i,x,n) for(int i=x; i<(n); ++i)
#define fixed_setprecision(n) fixed << setprecision((n))
#define execution_time(ti) printf("Execution Time: %.4lf sec\n", 1.0 * (clock() - ti) / CLOCKS_PER_SEC);
#define pai 3.1415926535897932384
#define NUM_MAX 2e18
#define NUM_MIN -1e9
 
using namespace std;
using ll = long long;
using P = pair<int,int>;
template<class T> inline bool chmax(T& a, T b){ if(a<b){ a=b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b){ if(a>b){ a=b; return 1; } return 0; }

int main() {
    vector<int> A(5);
    rep(i, 5) cin >> A[i];

    sort(A.begin(), A.end());


    if((A[0] == A[2] && A[3] == A[4]) || (A[0] == A[1] && A[2] == A[4])){
        cout << "Yes" << endl;
    }else{
        cout << "No" << endl;      
    }

    return 0;
} 

B - Ancestor

dfsかループでシミュレートします。

C++

#include <bits/stdc++.h>
 
#define rep(i,n) for(int i=0; i<(n); ++i)
#define repx(i,x,n) for(int i=x; i<(n); ++i)
#define fixed_setprecision(n) fixed << setprecision((n))
#define execution_time(ti) printf("Execution Time: %.4lf sec\n", 1.0 * (clock() - ti) / CLOCKS_PER_SEC);
#define pai 3.1415926535897932384
#define NUM_MAX 2e18
#define NUM_MIN -1e9
 
using namespace std;
using ll = long long;
using P = pair<int,int>;
template<class T> inline bool chmax(T& a, T b){ if(a<b){ a=b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b){ if(a>b){ a=b; return 1; } return 0; }

int main() {
    int N;
    cin >> N;
    vector<int> P(N+1);
    repx(i, 2,  N+1) cin >> P[i];

    int cnt=0;
    while(1){
        N = P[N];
        cnt++;
        if(N==1) break;
    }
    cout << cnt << endl;

    return 0;
} 

C - Monotonically Increasing

dfsを使うと綺麗に実装できます。

C++

#include <bits/stdc++.h>
 
#define rep(i,n) for(int i=0; i<(n); ++i)
#define repx(i,x,n) for(int i=x; i<(n); ++i)
#define fixed_setprecision(n) fixed << setprecision((n))
#define execution_time(ti) printf("Execution Time: %.4lf sec\n", 1.0 * (clock() - ti) / CLOCKS_PER_SEC);
#define pai 3.1415926535897932384
#define NUM_MAX 2e18
#define NUM_MIN -1e9
 
using namespace std;
using ll = long long;
using P = pair<int,int>;
template<class T> inline bool chmax(T& a, T b){ if(a<b){ a=b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b){ if(a>b){ a=b; return 1; } return 0; }

int N, M;
set<vector<int>> st;

void dfs(vector<int> v){
    if(v.size() == N){
        st.insert(v);
        return;
    }

    int i = 1;
    if(v.size()) i = v[v.size()-1] + 1;

    for(; i<=M; i++){
        v.push_back(i);
        dfs(v);
        v.pop_back();
    }
}

int main() {
    cin >> N >> M;

    dfs(vector<int>());

    for(vector<int> s:st){
        for(auto v:s){
            cout << v << ' ';
        }
        cout << endl;
    }

    return 0;
}