Submission #682812

#	Time	Username	Problem	Language	Result	Execution time	Memory
682812		iskhakkutbilim	Evacuation plan (IZhO18_plan)	C++14	10 / 100	4059 ms	33452 KiB

plan

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

#define int long long
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int N = 1e5;
const int M = 1e18;
int n, m, k;
vector< pair<int, int> > g[N];

int AEC[N], distanc[N];
vector<int> A, B;
set< pair<int, int> > q;

void dijkstra(int start, vector<int>&dis){
	for(int i = 0;i < n; i++) dis[i] = (i == start ? 0 : M);
	q.insert({dis[start], start});
	while(!q.empty()){
		int v = q.begin()->ss;
		q.erase(q.begin());
		for(auto [to, len] : g[v]){
			if(dis[to] > dis[v] + len){
				q.erase({dis[to], to});
				dis[to] = dis[v]+len;
				q.insert({dis[to], to});
				
				if(AEC[start]==0 and AEC[to] == 1){
					distanc[start] = min(distanc[start], dis[to]);
				}
				if(AEC[start]==1 and AEC[to] == 0){
					distanc[to] = min(distanc[to], dis[to]);
				}
			}
		}
	}
}

int used[N];
int s, t, ans;
void dfs(int v){
	used[v] = 1;
	if(v == t){
		int mn = M;
		for(int i = 0;i < n; i++){
			if(used[i] == 1){
				if(AEC[i] == 1) mn = 0;
				else
				mn = min(mn, distanc[i]);
			}
		}
		ans = max(ans, mn);
	}
	for(auto [to, len] : g[v]){
		if(used[to] == 0){
			dfs(to);
		}
	}
	used[v] = 0;
}

main(){
   ios::sync_with_stdio(0);
   cin.tie(0); cout.tie(0);
	cin >> n >> m;
	for(int i = 0;i < m; i++){
		int a, b, w; cin >> a >> b >> w;
		a--, b--;
		g[a].push_back({b, w});
		g[b].push_back({a, w});
	}
	vector<int> dis(n);
	cin >> k;
	for(int i = 0;i < k; i++){
		int a; cin >> a; a--;
		AEC[a] = 1;
	}
	for(int i = 0;i < n; i++){
		distanc[i] = M;
		if(AEC[i] == 0) B.push_back(i);
		else A.push_back(i);
	}
	if(k > (int)sqrt(n)){
		for(int start : B){
			dijkstra(start, dis);
		}
	}else{
		for(int start : A){
			dijkstra(start, dis);
		}
	}
	int Q; cin >> Q;
	if(n <= 15 and m <= 200 and Q <= 200){
		vector<vector<int>> dis1(n, vector<int>(n, -M));
		for(s = 0; s < n; s++){
			for(t = s+1; t < n; t++){
				ans = -M;
				for(int i = 0;i < n; i++) used[i] = 0;
				dfs(s);
				dis1[s][t] = ans;
			}
		}
		while(Q--){
			int a, b; cin >> a >> b; a--, b--;
			if(dis1[a][b] == -M and dis1[b][a] == -M) assert(false);
			if(dis1[a][b] == -M) cout << dis1[b][a];
			else cout << dis1[a][b];
			cout << '\n';
		}
	}else{
		while(Q--){
			int a, b; cin >> a >> b; a--, b--;
			if(AEC[a] == 1 or AEC[b] == 1){
				cout << 0 << '\n';
			}else{
				cout << min(distanc[a], distanc[b]) << '\n';
			}
		}
	}
	return 0;
}

Compilation message (stderr)

plan.cpp: In function 'void dijkstra(long long int, std::vector<long long int>&)':
plan.cpp:23:12: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   23 |   for(auto [to, len] : g[v]){
      |            ^
plan.cpp: In function 'void dfs(long long int)':
plan.cpp:55:11: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   55 |  for(auto [to, len] : g[v]){
      |           ^
plan.cpp: At global scope:
plan.cpp:63:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   63 | main(){
      | ^~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46