Submission #518902

#	Time	Username	Problem	Language	Result	Execution time	Memory
518902		sudheerays123	Ferries (NOI13_ferries)	C++17	28 / 40	234 ms	24396 KiB

ferries

#include <bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define ll long long int
#define tc ll test;cin >> test;while(test--)
#define vi vector<ll>
#define pll pair<ll,ll>
#define pb push_back
#define mp make_pair
#define INF 1e18
#define MOD 1000000007
#define ff first
#define ss second
#define in >>
#define out <<
#define space << " " <<
#define spacef << " "
#define fo(i,a,b) for(ll i = a; i <= b; i++)
#define nextline out "\n"
#define print(x) for(auto i : x ) cout out i spacef
#define mmax(x,i) x = max(x,i)
#define mmin(x,i) x = min(x,i)
#define N 100005

vector<bool> visited(N,false);
vi radj[N];

void dfs(ll s){

	if(visited[s]) return;
	visited[s] = true;
	for(auto u : radj[s]) dfs(u);
}

int main() {
    
    fast;

    ll n,m;
    cin in n in m;

	vector<pll> adj[n+5];

    fo(i,1,m){
        ll a,b,c;
        cin in a in b in c;

		adj[a].pb(mp(b,c));
		radj[b].pb(a);	
    }

	vi indegree(n+5,0);
	dfs(n);

	fo(i,1,n){
		for(auto u : radj[i]){
			if(visited[i] && visited[u]) indegree[u]++;
		}
	}

	vi dp(n+5); // dp[i] = minimum cost to come from N to i
	queue<ll> q;

	dp[n] = 0;
	q.push(n);

	while(!q.empty()){

		ll a = q.front();
		q.pop();

		if(a != n){

			vi first;
			vi second;

			ll cnt = 0;

			for(auto u : adj[a]){
				cnt++;
				if(visited[u.first]){
					first.pb(dp[u.first]);
					second.pb(u.second);
				}
				else{
					first.pb(INF);
					second.pb(u.second);
				}
			}

			if(first.size() != 0) sort(first.begin(),first.end());
			if(second.size() != 0) sort(second.rbegin(),second.rend());

			dp[a] = INF;
			fo(i,0,cnt-1) mmin(dp[a],first[i]+second[i]);
		}

		for(auto u : radj[a]){

			if(!visited[u]) continue;

			indegree[u]--;
			if(!indegree[u]) q.push(u);
		}
	}

	cout out dp[1];

    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 11 / 11
• Subtask 4: 0 / 12