Submission #677755

#	Time	Username	Problem	Language	Result	Execution time	Memory
677755		dooompy	Pipes (BOI13_pipes)	C++17	42.78 / 100	170 ms	18880 KiB

pipes

#include "bits/stdc++.h"

using namespace std;

void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
    cout << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
    while (l != r) cout << *l << " \n"[++l == r];
}
template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
    return o >> a.first >> a.second;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
    return o << '(' << a.first << ", " << a.second << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
    bool is = false;
    for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
    return o << '}';
}

#ifdef local
#define test(args...) abc("[" + string(#args) + "]", args)
#else
#define test(args...) void(0)
#endif

using ll = long long;

ll v[100005];
int deg[100005];

vector<pair<int, int>> adj[100005];
ll calc[500005];

bool seen[100005];

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
//    freopen("", "r", stdin);
//    freopen("", "w", stdout);
    int n, m; cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> v[i];
    for (int i = 1; i <= m; i++) {
        int a, b; cin >> a >> b;
        adj[a].push_back({b, i});
        adj[b].push_back({a, i});
        deg[a]++; deg[b]++;
    }

    queue<int> q;

    for (int i = 1; i <= n; i++) {
        if (deg[i] == 1) {
            q.push(i);
        }
    }

    while (!q.empty()) {
        // deg 1
        auto cur = q.front(); q.pop();
        seen[cur] = true;
        deg[cur] == 0;

        auto to = adj[cur][0];
        if (seen[to.first]) continue;
        ll weight = v[cur];

        v[to.first] -= weight;
        calc[to.second] = weight;

        if (--deg[to.first] == 1) {
            q.push(to.first);
        }
    }

    if (m == n - 1) {
        for (int i = 1; i <= m; i++) {
            cout << calc[i] * 2 << "\n";
        }
        return 0;
    }

    if (m > n || m % 2 == 0) {
        cout << 0 << endl;
        return 0;
    }

    for (int i = 1; i <= n; i++) {
        assert(deg[i] == 2);
    }
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:66:18: warning: statement has no effect [-Wunused-value]
   66 |         deg[cur] == 0;
      |         ~~~~~~~~~^~~~

• Subtask 1: 0 / 30
• Subtask 2: 42.77777777777778 / 70