Submission #610971

#	Time	Username	Problem	Language	Result	Execution time	Memory
610971		penguinhacker	Robot (JOI21_ho_t4)	C++17	100 / 100	992 ms	82248 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 changed edges leading to this node
map<int, ll> dp2[mxN]; // must use this color
map<int, vector<ar<int, 2>>> 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;
		adj[u][c].push_back({v, w});
		adj[v][c].push_back({u, w});
		mp[u][c]+=w;
		mp[v][c]+=w;
	}
	for (int i=0; i<n; ++i) {
		dp1[i]=INF;
		for (auto& x : adj[i])
			dp2[i][x.first]=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==-1) {
			for (auto& x : adj[u]) {
				int c=x.first;
				for (ar<int, 2> v : x.second) {
					ll cur=min(d+mp[u][c]-v[1], d+v[1]);
					if (cur<dp1[v[0]])
						pq.push({dp1[v[0]]=cur, v[0], -1});
					// change this edge and force this color
					if (d<dp2[v[0]][c])
						pq.push({dp2[v[0]][c]=d, v[0], c});
				}
			}
		} else {
			for (ar<int, 2> v : adj[u][t]) {
				ll cur=d+mp[u][t]-v[1];
				if (cur<dp1[v[0]])
					pq.push({dp1[v[0]]=cur, v[0], -1});
			}
		}
	}
	cout << (dp1[n-1]^INF?dp1[n-1]:-1);
	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:39:12: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   39 |   if (t==-1&&d^dp1[u]||~t&&d^dp2[u][t])
      |       ~~~~~^~~~~~~~~~

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