Submission #543933

#	Time	Username	Problem	Language	Result	Execution time	Memory
543933		Olympia	Senior Postmen (BOI14_postmen)	C++17	0 / 100	1096 ms	37744 KiB

postmen

#include <vector>
#include <algorithm>
#include <iostream>
#include <set>
#include <cmath>
#include <map>
#include <random>
#include <cassert>
#include <ctime>
#include <stack>
#include <cstdlib>
#include <queue>
#include <cstdio>
#include <limits.h>
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")

using namespace std;

vector<pair<int,int>> adj[(int)5e5];
bool hasVisited[(int)5e5];
bool okay[(int)5e5];

int main() {
    //freopen("balancing.in", "r", stdin);
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int N, M;
    scanf("%d%d", &N, &M);
    pair<int,int> edges[2 * M];
    for (int i = 0; i < M; i++) {
        int u, v;
        scanf("%d%d", &u, &v);
        u--, v--;
        edges[2 * i] = {u, v};
        edges[2 * i + 1] = {v, u};
        adj[u].emplace_back(v, 2 * i), adj[v].emplace_back(u, 2 * i + 1);
    }
    for (int i = 0; i < M; i++) {
        okay[i] = true;
    }
    stack<pair<int,int>> nodes;
    for (int i = 0; i < N; i++) {
        nodes.emplace(i, -1);
        while (!nodes.empty()) {
            int cur = nodes.top().first;
            okay[nodes.top().second] = false;
            hasVisited[cur] = true;
            bool upd = false;
            while (!adj[cur].empty()) {
                pair<int,int> pr = adj[cur].back();
                int j = adj[cur].back().first;
                if (pr.second == nodes.top().second || !okay[pr.second]) {
                    continue;
                }
                okay[pr.second] = false;
                if (hasVisited[j]) {
                    while (!nodes.empty() && nodes.top().first != j) {
                        hasVisited[nodes.top().first] = false;
                        printf("%d ", nodes.top().first + 1);
                        nodes.pop();
                    }
                    printf("%d\n", j + 1);
                } else {
                    nodes.emplace(j, pr.second);
                }
                upd = true;
                break;
            }
            if (!upd) {
                nodes.pop();
            }
        }
    }
}

Compilation message (stderr)

postmen.cpp:16: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   16 | #pragma GCC optimization ("O3")
      | 
postmen.cpp:17: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   17 | #pragma GCC optimization ("unroll-loops")
      | 
postmen.cpp: In function 'int main()':
postmen.cpp:30:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     scanf("%d%d", &N, &M);
      |     ~~~~~^~~~~~~~~~~~~~~~
postmen.cpp:34:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |         scanf("%d%d", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 38
• Subtask 2: 0 / 17
• Subtask 3: 0 / 45