Submission #405866

#	Time	Username	Problem	Language	Result	Execution time	Memory
405866		thomas_li	Toll (BOI17_toll)	C++17	8 / 100	3071 ms	8260 KiB

toll

// 57?
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pi;
const int MM = 5e4+5;
int n,o,k,m; ll dp[MM]; vector<pi> adj[MM];

int dfs(int u, int b){
	if(dp[u] != -1) return dp[u];
	if(u == b){
		dp[u] = 0;
		return 0;
	}
	dp[u] = 1e9;
	for(auto [v,w] : adj[u]){
		dfs(v,b);
		dp[u] =min(dp[u],dp[v]+w);
	}
	return dp[u];
}

int main(){
	cin.tie(0)->sync_with_stdio(0);
	cin >> k >> n >> m >> o;
	for(int i = 0; i < m; i++){
		int a,b,t; cin >> a >> b >> t;
		adj[a].emplace_back(b,t);
	}
	while(o--){
		int a,b; cin >> a >> b;
		memset(dp,-1,sizeof dp);
		dfs(a,b);
		cout << (dp[a]>=1e9 ? -1 : dp[a]) << "\n";
	}
}

• Subtask 1: 0 / 7
• Subtask 2: 0 / 10
• Subtask 3: 8 / 8
• Subtask 4: 0 / 31
• Subtask 5: 0 / 44