Submission #1205694

#	Time	Username	Problem	Language	Result	Execution time	Memory
1205694		PlayVoltz	Olympic Bus (JOI20_ho_t4)	C++20	5 / 100	1095 ms	5416 KiB

ho_t4

#include <cstdio>
#include <stdio.h>
#include <stdbool.h>
#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
#include <cassert>
using namespace std;

#define int long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second

int n;
vector<vector<pii> > graph;

int dijk(int s, int e){
	vector<int> dj(n+1, LLONG_MAX/4);
	priority_queue<pii, vector<pii>, greater<pii> > pq;
	pq.push(mp(0, s));
	while (pq.size()){
		int d=pq.top().fi, node=pq.top().se;
		pq.pop();
		if (d>=dj[node])continue;
		dj[node]=d;
		for (auto num:graph[node])pq.push(mp(d+num.se, num.fi));
	}
	return dj[e];
}

int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int m, ans=LLONG_MAX/4;
	cin>>n>>m;
	graph.resize(n+1);
	vector<pair<pii, pii> > edges(m);
	vector<vector<int> > dist(n+1, vector<int>(n+1, LLONG_MAX/2));
	for (int i=1; i<=n; ++i)dist[i][i]=0;
	for (int i=0, a, b, c, d; i<m; ++i){
		cin>>a>>b>>c>>d;
		edges[i]=mp(mp(a, b), mp(c, d));
		graph[a].pb(mp(b, c));
		dist[a][b]=min(dist[a][b], c);
	}
	for (int i=1; i<=n; ++i)for (int j=1; j<=n; ++j)for (int p=1; p<=n; ++p)dist[j][p]=min(dist[j][p], dist[j][i]+dist[i][p]);
	ans=min(ans, dijk(1, n)+dijk(n, 1));
	for (auto c:edges)if (c.se.se+min(dist[1][n], dist[1][c.fi.se]+dist[c.fi.fi][n]+c.se.fi)+min(dist[n][1], dist[n][c.fi.se]+dist[c.fi.fi][1]+c.se.fi)<ans){
		graph[c.fi.fi].erase(remove(graph[c.fi.fi].begin(), graph[c.fi.fi].end(), mp(c.fi.se, c.se.fi)));
		graph[c.fi.se].pb(mp(c.fi.fi, c.se.fi));
		ans=min(ans, dijk(1, n)+dijk(n, 1)+c.se.se);
		graph[c.fi.se].erase(remove(graph[c.fi.se].begin(), graph[c.fi.se].end(), mp(c.fi.fi, c.se.fi)));
		graph[c.fi.fi].pb(mp(c.fi.se, c.se.fi));
	}
	cout<<(ans==LLONG_MAX/4?-1:ans);
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63