Submission #610967

#	Time	Username	Problem	Language	Result	Execution time	Memory
610967		penguinhacker	Robot (JOI21_ho_t4)	C++17	34 / 100	3051 ms	50096 KiB

Main

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

#define ll long long
#define ar array

const int mxN=1e5;
const ll INF=1e18;
int n, m;
ll dp1[mxN]; // no change of edges leading to this node
vector<ll> dp2[mxN]; // changed the edge leading into this node
vector<ar<int, 4>> adj[mxN];
map<int, ll> mp[mxN];

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> m;
	for (int i=0; i<m; ++i) {
		int u, v, c, w;
		cin >> u >> v >> c >> w, --u, --v;
		int s1=adj[u].size(), s2=adj[v].size();
		adj[u].push_back({v, c, w, s2});
		adj[v].push_back({u, c, w, s1});
		mp[u][c]+=w;
		mp[v][c]+=w;
	}
	if (adj[n-1].empty()) {
		cout << -1;
		return 0;
	}
	for (int i=0; i<n; ++i) {
		dp1[i]=INF;
		dp2[i].assign(adj[i].size(), INF);
	}
	dp1[0]=0;
	priority_queue<ar<ll, 3>, vector<ar<ll, 3>>, greater<ar<ll, 3>>> pq;
	pq.push({0, 0, -1});
	while(pq.size()) {
		ll d=pq.top()[0];
		int u=pq.top()[1], t=pq.top()[2];
		pq.pop();
		if (t==-1&&d^dp1[u]||~t&&d^dp2[u][t])
			continue;
		if (~t)
			mp[u][adj[u][t][1]]-=adj[u][t][2];
		for (ar<int, 4> v : adj[u]) {
			ll cur=d+mp[u][v[1]]-v[2];
			if (cur<dp1[v[0]])
				pq.push({dp1[v[0]]=cur, v[0], -1});
			cur=d+v[2];
			if (cur<dp2[v[0]][v[3]])
				pq.push({dp2[v[0]][v[3]]=cur, v[0], v[3]});
		}
		if (~t)
			mp[u][adj[u][t][1]]+=adj[u][t][2];
	}
	ll ans=min(dp1[n-1], *min_element(dp2[n-1].begin(), dp2[n-1].end()));
	cout << (ans==INF?-1:ans);
	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:43:12: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   43 |   if (t==-1&&d^dp1[u]||~t&&d^dp2[u][t])
      |       ~~~~~^~~~~~~~~~

• Subtask 1: 34 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42