Submission #676470

#	Time	Username	Problem	Language	Result	Execution time	Memory
676470		penguin133	Sightseeing (NOI14_sightseeing)	C++17	25 / 25	2115 ms	134236 KiB

sightseeing

#include <bits/stdc++.h>
using namespace std;
int parent[500005];//whatever max number of nodes + 5 (for 1-index)
vector<pair<int, pair<int, int > > >v;
int dist[500005];
int visited[500005];
vector<pair<int, int> >v1[500005];
void ufdsinit(int n) {
    for(int i = 0;i<=n;i++)parent[i] = i; //each node is its own set
}
int findset(int a) {
	if(parent[a] == a) return a; //we reached the head
else {
		parent[a] = findset(parent[a]); //use recursion to go to the parent 
		return parent[a]; //path compression
	}
}
void mergeset(int a,int b) {
	int pa = findset(a);
	int pb = findset(b);
	if(pa!=pb)  //if they are a different set
		parent[pb] = pa; //merge them together
}
void dfs(int root, int mini){
	if(visited[root] == 1)return;
	visited[root] = 1;
	for(int i=0;i<v1[root].size();i++){
		int a = v1[root][i].first;
		int b = v1[root][i].second;
		mini = min(mini, b);
		dist[a] = max(dist[a], mini);
		dfs(a, mini);
	}
}

int main(){
	ios::sync_with_stdio(0);cin.tie(0);
	int n,e,q;
	cin >> n >> e >> q;
	for(int i=0;i<e;i++){
		int a,b,c;
		cin >> a >> b >> c;
		v.push_back(make_pair(c, make_pair(a,b)));
	}
	ufdsinit(n);
	sort(v.begin(), v.end());
	for(int i=v.size()-1;i>=0;i--){
		long long a = v[i].first;
		int b = v[i].second.first;
		int c = v[i].second.second;
		if(findset(b) == findset(c))continue;
		mergeset(b,c);
		v1[b].push_back(make_pair(c, a));
		v1[c].push_back(make_pair(b, a));
	}
	dfs(1, 1e9+5);
	for(int i=0;i<q;i++){
		int a;
		cin >> a;
		cout << dist[a] << "\n";
	}
}

Compilation message (stderr)

sightseeing.cpp: In function 'void dfs(int, int)':
sightseeing.cpp:27:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |  for(int i=0;i<v1[root].size();i++){
      |              ~^~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 6 / 6
• Subtask 4: 10 / 10