Submission #147819

#	Time	Username	Problem	Language	Result	Execution time	Memory
147819		luciocf	Cities (BOI16_cities)	C++14	14 / 100	341 ms	24684 KiB

cities

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, int> pii;

const int maxn = 2e5+10;
const ll inf = 1e18+10;

int n, cnt=-1;
int a[6];

ll dist[3][maxn];

bool mark[maxn];

vector<pii> grafo[maxn];

void dijkstra(int s)
{
	++cnt;

	memset(mark, 0, sizeof mark);

	for (int i = 1; i <= n; i++)
		dist[cnt][i] = inf;

	priority_queue<pii, vector<pii>, greater<pii>> fila;

	dist[cnt][s] = 0, fila.push({0, s});

	while (!fila.empty())
	{
		int u = fila.top().second; fila.pop();

		if (mark[u]) continue;
		mark[u] = 1;

		for (auto pp: grafo[u])
		{
			int v = pp.first, w = pp.second;

			if (dist[cnt][v] > dist[cnt][u]+1ll*w)
			{
				dist[cnt][v] = dist[cnt][u]+1ll*w;
				fila.push({dist[cnt][v], v});
			}
		}
	}
}

int main(void)
{
	int m, k;
	scanf("%d %d %d", &n, &k, &m);

	for (int i = 1; i <= k; i++)
		scanf("%d", &a[i]);

	for (int i = 1; i <= m; i++)
	{
		int u, v, w;
		scanf("%d %d %d", &u, &v, &w);

		grafo[u].push_back({v, w}); grafo[v].push_back({u, w});
	}

	if (k == 2)
	{
		int u = a[1], v = a[2];

		dijkstra(u);

		printf("%lld\n", dist[0][v]);
	}
	else
	{
		int u = a[1], v = a[2], w = a[3];

		dijkstra(u);
		dijkstra(v);
		dijkstra(w);

		ll ans = inf;

		for (int i = 1; i <= n; i++)
			if (dist[0][i] != inf && dist[1][i] != inf && dist[2][i] != inf)  
				ans = min(ans, dist[0][i]+dist[1][i]+dist[2][i]);

		printf("%lld\n", ans);
	}
}

Compilation message (stderr)

cities.cpp: In function 'int main()':
cities.cpp:56:7: 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:59:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ~~~~~^~~~~~~~~~~~~
cities.cpp:64:8: 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: 14 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 26