Submission #392038

#	Time	Username	Problem	Language	Result	Execution time	Memory
392038		negar_a	Cities (BOI16_cities)	C++14	0 / 100	7 ms	5196 KiB

cities

//!yrt tsuj uoy srettam gnihton no emoc
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;

typedef long long ll;
typedef long double ld;
#define pb push_back
#define mp make_pair
#define pii pair <ll, ll>
#define fast_io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define F first
#define S second

const int maxn = 1e5 + 5;
int im[maxn];
vector <pii> adj[maxn];
ll dp[maxn][35];
ll inf = 1e17;
int n, m, k;
bool mark[maxn];

int main(){
	fast_io;
	scanf("%d %d %d", &n, &k, &m);
	for(int i = 0; i < k; i ++){
		cin >> im[i];
		im[i] --;
	}
	for(int i = 0; i < m; i ++){
		int x, y;
		ll w;
		scanf("%d %d %lld", &x, &y, &w);
		x --; y --;
		adj[x].pb({y, w});
		adj[y].pb({x, w});
	}
	ll ans = inf;
	for(int mask = 0; mask < (1 << k); mask ++){
		for(int i = 0; i < n; i ++){
			dp[i][mask] = inf;
		}
	}
	for(int i = 0; i < k; i ++){
		dp[im[i]][1 << i] = 0;
	}
	for(int mask = 1; mask < (1 << k); mask ++){
		for(int m1 = mask; m1; m1 = (m1 - 1) & mask){
			for(int i = 0; i < n; i ++){
				dp[i][mask] = min(dp[i][mask], dp[i][mask ^ m1] + dp[i][m1]);
			}
		}
		
		queue <pii> s;
		for(int i = 0; i < n; i ++){
			if(dp[i][mask] < inf){
				s.push({dp[i][mask], i});
			}
		}
		while(s.size()){
			ll we = s.front().F;
			int x = s.front().S;
			mark[x] = false;
			s.pop();
			for(auto u : adj[x]){
				if(dp[u.F][mask] > dp[x][mask] + u.S){
					dp[u.F][mask] = dp[x][mask] + u.S;
					if(!mark[u.F]){		
						s.push({dp[u.F][mask], u.F});
						mark[u.F] = true;
					}
				}
			}
		}
	}
	for(int i = 0; i < n; i ++){
		ans = min(ans, dp[i][(1 << k) - 1]);
	}
	printf("%lld", ans);
	
	return 0;
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:61:7: warning: unused variable 'we' [-Wunused-variable]
   61 |    ll we = s.front().F;
      |       ^~
cities.cpp:25:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   25 |  scanf("%d %d %d", &n, &k, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
cities.cpp:33:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   33 |   scanf("%d %d %lld", &x, &y, &w);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 22
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 26