oj.uz

Submission #38884

# Submission time Handle Problem Language Result Execution time Memory
38884 2018-01-07T14:29:02 Z cheater2k Sightseeing (NOI14_sightseeing) C++14
15 / 25
 2699 ms 91456 KB 
#include <bits/stdc++.h>
using namespace std;

const int N = 500005;

int n, m, q;
int dsu[N];
vector< pair<int, pair<int,int> > > edges;
vector< pair<int,int> > G[N];
int mn[N];

int anc(int p) { return p == dsu[p] ? p : dsu[p] = anc(dsu[p]); }
void join(int p, int q) { p = anc(p); q = anc(q); dsu[p] = q; }

int main() {
	scanf("%d %d %d", &n, &m, &q);
	for (int i = 0; i < m; ++i) {
		int u, v, w; scanf("%d %d %d", &u, &v, &w);
		edges.push_back(make_pair(w, make_pair(u, v))); // w <= 1e5
	}
	// build maximum spanning tree
	for (int i = 1; i <= n; ++i) dsu[i] = i;
	sort(edges.begin(), edges.end());
	for (int i = m - 1; i >= 0; --i) {
		int w = edges[i].first;
		int u = edges[i].second.first;
		int v = edges[i].second.second;
		if (anc(u) == anc(v)) continue;
		join(u, v);
		G[u].push_back(make_pair(w, v));
		G[v].push_back(make_pair(w, u));
	}

	for (int i = 1; i <= n; ++i) mn[i] = -1;
	mn[1] = 1e9;
	// bfs
	queue <int> qu; qu.push(1);
	while(!qu.empty()) {
		int u = qu.front(); qu.pop();
		for (int i = 0; i < G[u].size(); ++i) {
			int v = G[u][i].second, w = G[u][i].first;
			if (mn[v] == -1) {
				mn[v] = min(mn[u], w); qu.push(v);
			}
		}
	}
	
	// answer queries
	while(q-- > 0) {
		int u; scanf("%d", &u);
		printf("%d\n", mn[u]);
	}
}

Compilation message

sightseeing.cpp: In function 'int main()':
sightseeing.cpp:40:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < G[u].size(); ++i) {
                     ^
sightseeing.cpp:16:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d", &n, &m, &q);
                               ^
sightseeing.cpp:18:45: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u, v, w; scanf("%d %d %d", &u, &v, &w);
                                             ^
sightseeing.cpp:50:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u; scanf("%d", &u);
                         ^

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 17644 KB Output is correct
2 Correct 3 ms 17644 KB Output is correct

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 17816 KB Output is correct
2 Correct 0 ms 17644 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 19680 KB Output is correct
2 Correct 39 ms 19680 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2699 ms 91456 KB Output is correct
2 Runtime error 0 ms 0 KB -1: Interrupted system call