Submission #543935

#	Time	Username	Problem	Language	Result	Execution time	Memory
543935		Olympia	Senior Postmen (BOI14_postmen)	C++17	38 / 100	941 ms	17524 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 ("O1")
#pragma GCC optimization ("unroll-loops")

using namespace std;

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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int N, M;
    scanf("%d%d", &N, &M);
    for (int i = 0; i < M; i++) {
        int u, v;
        scanf("%d%d", &u, &v);
        u--, v--;
        adj[u].push_back(i), adj[v].push_back(i);
        edges[i] = {u, v};
    }
    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);
        bool upd;
        while (!nodes.empty()) {
            int cur = nodes.top().first; int prev = nodes.top().second;
            okay[prev] = false;
            hasVisited[cur] = true;
            upd = false;
            for (int pr: adj[cur]) {
                int j = edges[pr].first;
                if (cur == edges[pr].first) j = edges[pr].second;
                if (pr == prev || !okay[pr]) {
                    continue;
                }
                okay[pr] = false;
                if (hasVisited[j]) {
                    while (!nodes.empty()) {
                        int &x = nodes.top().first; if (x == j) break;
                        hasVisited[x] = false;
                        printf("%d ", x + 1);
                        nodes.pop();
                    }
                    printf("%d\n", j + 1);
                } else {
                    nodes.emplace(j, pr);
                }
                upd = true;
                break;
            }
            if (!upd) {
                nodes.pop();
            }
        }
    }
}

Compilation message (stderr)

postmen.cpp:16: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   16 | #pragma GCC optimization ("O1")
      | 
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:33:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         scanf("%d%d", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~

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