Submission #1038124

#	Time	Username	Problem	Language	Result	Execution time	Memory
1038124		stdfloat	Palembang Bridges (APIO15_bridge)	C++17	0 / 100	1 ms	348 KiB

bridge

#include <bits/stdc++.h>
using namespace std;

using ll = long long;

#define int long long

#define ff  first
#define ss  second
#define pii pair<int, int>

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);

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

    int tx;
    vector<int> dis(n, LLONG_MAX);
    vector<set<int>> p(n);
    priority_queue<pii> q;
    for (int i = 0; i < m; i++) {
        int x, y;
        cin >> x >> y;

        p[x].insert(y);

        if (!i) {
            dis[x] = 0;
            q.push({0, x});
        }
        else if (i == 1) tx = x;
    }

    while (!q.empty()) {
        auto [d, x] = q.top(); d = -d; q.pop();

        if (d != dis[x]) continue;

        for (auto j : p[x]) {
            for (int i = x + j; i < n && p[i].find(j) == p[i].end(); i += j) {
                if (!p[i].empty() && d + abs(i - x) / j < dis[i]) {
                    dis[i] = d + abs(i - x) / j;
                    q.push({-dis[i], i});
                }
            }
            for (int i = x - j; i >= 0 && p[i].find(j) == p[i].end(); i -= j) {
                if (!p[i].empty() && d + abs(i - x) / j < dis[i]) {
                    dis[i] = d + abs(i - x) / j;
                    q.push({-dis[i], i});
                }
            }
        }
    }

    cout << (dis[tx] == LLONG_MAX ? -1 : dis[tx]);
}

Compilation message (stderr)

bridge.cpp: In function 'int32_t main()':
bridge.cpp:56:20: warning: 'tx' may be used uninitialized in this function [-Wmaybe-uninitialized]
   56 |     cout << (dis[tx] == LLONG_MAX ? -1 : dis[tx]);
      |                    ^

• Subtask 1: 0 / 8
• Subtask 2: 0 / 14
• Subtask 3: 0 / 9
• Subtask 4: 0 / 32
• Subtask 5: 0 / 37