dut新生大礼包3

A

https://atcoder.jp/contests/abc177/tasks/abc177_c?lang=en

#include <bits/stdc++.h>

using namespace std;

const int P = 1000000007;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    vector<int> a(n);
    for(int i = 0; i < n; ++i) {
        cin >> a[i];
    }

    long long ans = 0;
    long long sum = 0;
    for(int i = 0; i < n; ++i) {
        ans = (ans + sum * a[i]) % P;
        sum = (sum + a[i]) % P;
    }

    cout << ans << '\n';

    return 0;
}

B

https://atcoder.jp/contests/abc177/tasks/abc177_d?lang=en

#include <bits/stdc++.h>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;

    vector<vector<int> > G(n);
    for(int i = 0; i < m; ++i) {
        int a, b;
        cin >> a >> b;
        --a; --b;
        G[a].emplace_back(b);
        G[b].emplace_back(a);
    }

    vector<bool> vis(n);

    int ans = 0;
    for(int i = 0; i < n; ++i) {
        if(!vis[i]) {
            int cnt = 0;
            queue<int> q;
            q.emplace(i);
            vis[i] = true;
            while(!q.empty()) {
                int u = q.front();
                q.pop();
                cnt += 1;
                for(int v : G[u]) {
                    if(!vis[v]) {
                        vis[v] = true;
                        q.emplace(v);
                    }
                }
            }
            ans = max(ans, cnt);
        }
    }

    cout << ans << '\n';

    return 0;
}

C

https://atcoder.jp/contests/abc183/tasks/abc183_c?lang=en

#include <bits/stdc++.h>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;

    vector<vector<int> > t(n, vector<int> (n));
    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < n; ++j) {
            cin >> t[i][j];
        }
    }

    vector<int> id(n);
    iota(id.begin(), id.end(), 0);

    int ans = 0;

    do {
        int sum = 0;
        for(int i = 0; i < n; ++i) {
            sum += t[id[i]][id[(i + 1) % n]];
        }
        if(sum == k) {
            ans += 1;
        }
    } while(next_permutation(id.begin(), id.end()));

    cout << ans / n << '\n';

    return 0;
}

D

https://atcoder.jp/contests/abc183/tasks/abc183_d?lang=en

#include <bits/stdc++.h>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, w;
    cin >> n >> w;

    vector<int> s(n);
    vector<int> t(n);
    vector<int> p(n);
    for(int i = 0; i < n; ++i) {
        cin >> s[i] >> t[i] >> p[i];
    }

    vector<long long> sum(200001);
    for(int i = 0; i < n; ++i) {
        sum[s[i]] += p[i];
        sum[t[i]] -= p[i];
    }

    for(int i = 0; i < 200000; ++i) {
        sum[i + 1] += sum[i];
    }

    if(*max_element(sum.begin(), sum.end()) > w) {
        cout << "No" << '\n';
    } else {
        cout << "Yes" << '\n';
    }

    return 0;
}

E

https://atcoder.jp/contests/abc182/tasks/abc182_c?lang=en

#include <bits/stdc++.h>

using namespace std;

int main() {
    long long n;
    cin >> n;

    vector<int> b;
    while(n) {
        b.emplace_back(n % 10);
        n /= 10;
    }

    int m = b.size();
    int ans = m;
    for(int i = 0; i < 1 << m; ++i) {
        int sum = 0;
        for(int j = 0; j < m; ++j) {
            if(i >> j & 1) {
                sum += b[j];
            }
        }
        if(sum % 3 == 0) {
            ans = min(ans, m - __builtin_popcount(i));    
        }
    }

    if(ans == m) {
        cout << -1 << '\n';
    } else {
        cout << ans << '\n';
    }

    return 0;
}

F

https://atcoder.jp/contests/abc182/tasks/abc182_d?lang=en

#include <bits/stdc++.h>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    vector<int> a(n);
    for(int i = 0; i < n; ++i) {
        cin >> a[i];
    }

    vector<long long> pre(n + 1);
    vector<long long> mx(n + 1);
    for(int i = 0; i < n; ++i) {
        pre[i + 1] = pre[i] + a[i];
        mx[i + 1] = max(mx[i], pre[i + 1]);
    }

    long long cur = 0;
    long long ans = 0;
    for(int i = 1; i <= n; ++i) {
        ans = max(ans, cur + mx[i]);
        cur += pre[i];
    }

    cout << ans << '\n';

    return 0;
}

G

https://atcoder.jp/contests/abc180/tasks/abc180_c?lang=en

#include <bits/stdc++.h>

using namespace std;

int main() {
    long long n;
    cin >> n;

    vector<long long> ans;
    for(long long i = 1; i * i <= n; ++i) {
        if(n % i == 0) {
            ans.emplace_back(i);
            ans.emplace_back(n / i);
        }
    }

    sort(ans.begin(), ans.end());
    ans.erase(unique(ans.begin(), ans.end()), ans.end());

    for(long long i : ans) {
        cout << i << '\n';
    }

    return 0;
}

H

https://atcoder.jp/contests/abc170/tasks/abc170_d?lang=en

#include <bits/stdc++.h>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    int m = 1000001;

    vector<int> a(n);
    vector<int> cnt(m);
    vector<bool> vis(m);

    for(int i = 0; i < n; ++i) {
        cin >> a[i];
        cnt[a[i]] += 1;
    }

    for(int i = 1; i < m; ++i) {
        if(cnt[i] > 0) {
            for(int j = i + i; j < m; j += i) {
                vis[j] = true;
            }
        }
    }

    long long ans = n;

    for(int i : a) {
        if(cnt[i] > 1 || vis[i]) {
            ans -= 1;
        }
    }

    cout << ans << '\n';

    return 0;
}