Submission #37327

#	Time	Username	Problem	Language	Result	Execution time	Memory
37327		szawinis	Cities (BOI16_cities)	C++14	0 / 100	2523 ms	41116 KiB

cities

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, int> pli;
const int N = 1e5+1;
const ll INF = 1e17+1;

int n, k, m;
vector<int> s;
vector<pair<int,int> > g[N];
ll ans = INF, d[5][N], d2[1 << 5][N], res[1 << 5];
priority_queue<pli, vector<pli>, greater<pli> > pq;
int main() {
	scanf("%d %d %d", &n, &k, &m);
	for(int i = 0, v; i < k; i++) {
		scanf("%d", &v);
		s.push_back(v-1);
	}

	for(int i = 0, u, v, w; i < m; i++) {
		scanf("%d %d %d", &u, &v, &w);
		g[u-1].emplace_back(v-1, w);
		g[v-1].emplace_back(u-1, w);
	}

	for(int i = 0; i < k; i++) {
		fill(d[i], d[i]+n, INF);
		d[i][s[i]] = 0;
		pq.emplace(0, s[i]);
		while(!pq.empty()) {
			int u = pq.top().second;
			pq.pop();
			for(auto p: g[u]) if(d[i][u] + p.second < d[i][p.first]) {
				d[i][p.first] = d[i][u] + p.second;
				pq.emplace(d[i][p.first], p.first);
			}
		}
	}

	for(int mask = 0; mask < 1 << k; mask++) {
		for(int v = 0; v < n; v++) d2[mask][v] = INF;
		res[mask] = INF;
	}

	for(int i = 0; i < k; i++) d2[1 << i][s[i]] = res[1 << i] = 0;
	for(int mask = 1; mask < (1 << k)-1; mask++) {// chec klimits
		for(int v = 0; v < n; v++) if(!d2[mask][v]) pq.emplace(0, v);
		while(!pq.empty()) {
			int u = pq.top().second;
			pq.pop();
			for(auto p: g[u]) if(d2[mask][u] + p.second < d2[mask][p.first]) {
				d2[mask][p.first] = d2[mask][u] + p.second;
				pq.emplace(d2[mask][p.first], p.first);
			}
		}
		for(int i = 0; i < k; i++) if(!(mask >> i & 1)) {
			int new_mask = mask | 1 << i;
			for(int v = 0; v < n; v++) {
				if(!d2[mask][v] || d2[mask][v] + d[i][v] == d2[mask][s[i]])
					d2[new_mask][v] = 0;
			}
			res[new_mask] = min(res[mask] + d2[mask][s[i]], res[new_mask]);
		}
	}
	printf("%lld", res[(1 << k) - 1]);
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:14:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d", &n, &k, &m);
                               ^
cities.cpp:16:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &v);
                  ^
cities.cpp:21:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d", &u, &v, &w);
                                ^

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