Submission #495174

#	Time	Username	Problem	Language	Result	Execution time	Memory
495174		Ziel	Evacuation plan (IZhO18_plan)	C++17	54 / 100	4049 ms	49416 KiB

plan

/**
 * LES GREATEABLES BRO TEAM
**/

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
#define sz(x) (int)x.size()
const bool FLAG = false;
void setIO(const string &f = "");

signed main() {
    setIO();
    
    int n, m;
    cin >> n >> m;
    vector<vector<pair<int, int>>> adj(n + 1);
    set<pair<int, int>> edges;
    for (int i = 0, x, y, z; i < m; i++) {
    	cin >> x >> y >> z;
    	adj[x].push_back({y, z});
    	adj[y].push_back({x, z});
    	edges.insert({min(x, y), max(x, y)});
    }

    int k;
    cin >> k;
    vector<int> g(k + 1), d(n + 1, 1e9 + 17);
    set<int> npp;
    for (int i = 1; i <= k; i++) {
    	cin >> g[i];
    	npp.insert(g[i]);
    }

    {
    	set<pair<int, int>> q;
    	for (int i = 1; i <= k; i++) {
    		q.insert({0, g[i]});
    		d[g[i]] = 0;
    	}
		while (sz(q)) {
			int v = q.begin()->second;
			q.erase(q.begin());

			for (auto [to, len]: adj[v]) {
				if (d[to] > d[v] + len) {
					q.erase({d[to], to});
					d[to] = d[v] + len;
					q.insert({d[to], to});
				}
			}
		}
    }

    int qr;
    cin >> qr;

    while (qr--) {
    	int s, t;
    	cin >> s >> t;
    	if (edges.count({min(s, t), max(s, t)})) {
    		cout << min(d[s], d[t]) << '\n';
    	} else if (npp.count(s) || npp.count(t)) {
    		cout << "0\n";
    	} else {
   			set<pair<int, int>> q;
   			vector<int> d2(n + 1, 0);
   			q.insert({d[s], s});
   			d2[s] = d[s];
    		while (sz(q)) {
		    	int v = q.begin()->second;
    			q.erase(q.begin());

    			for(auto [to, len]: adj[v]) {
    				int dd = min(d[to], d2[v]);
    				if (d2[to] < dd) {
    					q.erase({-d2[to], to});
		    			d2[to] = dd;
    					q.insert({-d2[to], to});
    				}
    			}
	    	}
	    	cout << min(d2[s], d2[t]) << '\n';
    	}
    }

    
    return 0;
}

void setIO(const string &f) {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (fopen((f + ".in").c_str(), "r")) {
        freopen((f + ".in").c_str(), "r", stdin);
        freopen((f + ".out").c_str(), "w", stdout);
    }
}

Compilation message (stderr)

plan.cpp: In function 'void setIO(const string&)':
plan.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen((f + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen((f + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 0 / 46