Submission #956537

#	Time	Username	Problem	Language	Result	Execution time	Memory
956537		pragmatist	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	218 ms	26904 KiB

commuter_pass

#include <bits/stdc++.h>

using namespace std;

const int N = (int)1e5+20;
const int inf = (int)1e9+7;
const long long INF = (long long)1e18+7;
const int MOD = 42043;

int sum(int x, int y) {
	x += y;
	if(x >= MOD) {
		x -= MOD;
	}
	return x;
}

int mult(int x, int y) {
	return 1ll*x*y%MOD;
}

struct Edge {
	int u, v, w;
};

int n, m, s1, t1, s2, t2;
vector<pair<int, int> > g[N];
vector<int> g2[N];
long long d[4][N];

void dijkstra(int tp, int s) {
	fill(d[tp],  d[tp]+1+n, INF);
	d[tp][s] = 0;
	priority_queue<pair<long long, int> > q;
	q.push({0, s});
	while(!q.empty()) {
		long long cur_d = -q.top().first;
		int v = q.top().second;
		q.pop();
		if(cur_d>d[tp][v]) {
			continue;
		}
		for(auto [to, w] : g[v]) {
			if(d[tp][v]+w < d[tp][to]) {
				d[tp][to] = d[tp][v]+w;
				q.push({-d[tp][to], to});
			}
		}
	}	
}

bool used[N];
long long ans, mn1[N], mn2[N];

void dfs(int v) {  	
	used[v] = 1;
	mn1[v] = d[2][v];
	mn2[v] = d[3][v];
	for(auto to : g2[v]) {
		if(!used[to]) {
			dfs(to);
		}
		mn1[v] = min(mn1[v], mn1[to]);
		mn2[v] = min(mn2[v], mn2[to]);		
	}
	ans = min(ans, d[2][v]+mn2[v]);
	ans = min(ans, d[3][v]+mn1[v]);
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
	cin >> n >> m >> s1 >> t1 >> s2 >> t2;
	vector<Edge> e;
	for(int i = 1; i <= m; ++i) {
		int u, v, w;
		cin >> u >> v >> w;
		e.push_back({u, v, w});
		g[u].push_back({v, w});
		g[v].push_back({u, w});
	}
	dijkstra(0, s1);
	dijkstra(1, t1);
	dijkstra(2, s2);
	dijkstra(3, t2);
	ans = d[2][t2];
	for(auto [u, v, w] : e) {
	    if(d[0][u]+w+d[1][v]==d[0][t1]) {
			g2[u].push_back(v);	    	
	    }
	    if(d[1][u]+w+d[0][v]==d[0][t1]) {
			g2[v].push_back(u);	    	
	    }
	}
	for(int i = 1; i <= n; ++i) {
		if(!used[i]) {
			dfs(i);
		}
	}
	cout << ans;
	return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45