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답안 #91122

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
91122 2018-12-26T10:08:57 Z Just_Solve_The_Problem 관광지 (IZhO14_shymbulak) C++11
0 / 100
 1500 ms 11548 KB 
#include <bits/stdc++.h>

using namespace std;

#define ll long long

const int N = (int)2e5 + 7;

vector < int > gr[N];
int n;
int used[N], deg[N];
ll ans = 0;
int diam;
int dist[N], us[N], id[N];
vector < int > node;

void bfs(int v) {
	memset(used, 0, sizeof used);
	queue < int > q;
	q.push(v);
	used[v] = 1;
	while (!q.empty()) {
		v = q.front();
		q.pop();
		for (int to : gr[v]) {
			if (used[to] == 0) {
				used[to] = used[v] + 1;
				q.push(to);
			}
		}
	}
}

void bfs1(int v) {
	memset(dist, 0, sizeof dist);
	queue < int > q;
	q.push(v);
	dist[v] = 1;
	int asd = v;
	int res = 0;
	int mx = 0;
	while (!q.empty()) {
		v = q.front();
		q.pop();
		for (int to : gr[v]) {
			if (dist[to] == 0) {
				dist[to] = dist[v] + 1;
				mx = max(mx, dist[to]);
				q.push(to);
			} else if (dist[v] + 1 == dist[to]) {
				res = id[to];
			}
		}
	}
	if (mx - 1 == diam) {
		int val = 0;
		for (int i = 1; i <= n; i++) {
			if (mx == dist[i]) val++;
		}
		ans += val;
		if (res) {
			val = 0;
			for (int i = 1; i <= n; i++) {
				if (id[i] == res && dist[i] == mx) val++;
			} 
			ans += val;
		}
	}
}

void dfs1(int v, int pr) {
	node.push_back(v);
	us[v] = 1;
	for (int to : gr[v]) {
		if (us[to] || used[to] != 2) continue;
		dfs1(to, v);
	}
}

void dfs2(int v, int pr) {
	for (int to : gr[v]) {
		if (to == pr || used[to] == 2) continue;
		id[to] = id[v];
		dfs2(to, v);
	}
}

main() {
	iota(id, id + N, 0);
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
		int u, v;
		scanf("%d %d", &u, &v);
		gr[u].push_back(v);
		gr[v].push_back(u);
		deg[u]++;
		deg[v]++;
	}
	int mx = 0;
	bfs(1);
	for (int i = 1; i <= n; i++) {
		if (used[i] > used[mx]) mx = i;
	} 
	bfs(mx);
	mx = 0;
	for (int i = 1; i <= n; i++) {
		if (used[i] > used[mx]) {
			mx = i;
		}
	}
	diam = used[mx] - 1;
	for (int i = 1; i <= n; i++) {
		if (gr[i].size() == 1) {
			node.push_back(i);
		}
	}
	memset(used, 0, sizeof used);
	for (int i = 0; i < n; i++) {
		if (i == node.size()) {
			break;
		}
		int v = node[i];
		used[v] = 1;
		for (int to : gr[v]) {
			if (!used[to]) {
				deg[to]--;
				if (deg[to] <= 1) {
					node.push_back(to);
				}
			}
		}
	}
	for (int i = 1; i <= n; i++) {
		if (!used[i]) {
			used[i] = 2;
		}
	}
	while (!node.empty()) node.pop_back();
	for (int i = 1; i <= n; i++) {
		if (used[i] == 2) {
			dfs1(i, i);
			break;
		}
	}
	for (int i = 1; i <= n; i++) {
		if (used[i] == 2) {
			dfs2(i, i);
		}
	}
	for (int i = 1; i <= n; i++) {
		bfs1(i);
	}
	cout << ans / 2;
}

Compilation message

shymbulak.cpp: In function 'void bfs1(int)':
shymbulak.cpp:39:6: warning: unused variable 'asd' [-Wunused-variable]
  int asd = v;
      ^~~
shymbulak.cpp: At global scope:
shymbulak.cpp:88:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^
shymbulak.cpp: In function 'int main()':
shymbulak.cpp:119:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (i == node.size()) {
       ~~^~~~~~~~~~~~~~
shymbulak.cpp:90:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
shymbulak.cpp:93:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 7416 KB Output is correct
2 Correct 8 ms 7508 KB Output is correct
3 Correct 8 ms 7508 KB Output is correct
4 Correct 8 ms 7508 KB Output is correct
5 Correct 9 ms 7508 KB Output is correct
6 Correct 8 ms 7508 KB Output is correct
7 Correct 8 ms 7508 KB Output is correct
8 Correct 8 ms 7508 KB Output is correct
9 Correct 8 ms 7628 KB Output is correct
10 Correct 8 ms 7628 KB Output is correct
11 Correct 9 ms 7672 KB Output is correct
12 Correct 8 ms 7676 KB Output is correct
13 Correct 14 ms 7684 KB Output is correct
14 Correct 31 ms 7688 KB Output is correct
15 Incorrect 30 ms 7944 KB Output isn't correct

Subtask #2
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 41 ms 7944 KB Output is correct
2 Correct 41 ms 7944 KB Output is correct
3 Incorrect 54 ms 7944 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 50.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1545 ms 11548 KB Time limit exceeded
2 Halted 0 ms 0 KB -