oj.uz

답안 #309580

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
309580 2020-10-03T20:20:13 Z bigg Mousetrap (CEOI17_mousetrap) C++14
45 / 100
 924 ms 60280 KB 
#include<bits/stdc++.h>
using namespace std;
const int MAXN = 1e6 + 10;
vector<int> grafo[MAXN];
int dp[MAXN];

pair<int, int > inserts(int x, pair<int, int> p){
	if(x >= p.first) swap(p.first, p.second), p.first = x;
	else if(x > p.second) p.second = x;
	return p;
}

void dfs(int x, int p){
	pair<int, int> par = make_pair(-1, -1);
	for(int i = 0; i < grafo[x].size(); i++){
		int viz = grafo[x][i];
		if(viz == p) continue;
		dfs(viz, x);
		par = inserts(dp[viz], par);
	}
	for(int i = 0 ; i < grafo[x].size(); i++){
		int viz = grafo[x][i];
		if(viz == p) swap(grafo[x][i], grafo[x].front());
	}
	if(grafo[x].size() == 1) dp[x] = 0;
	else{
		dp[x] = (grafo[x].size() == 2) ? 1 : par.second + grafo[x].size() - 1;
	}
	//printf("%d\n", dp[x]);
}
int n, t, m;
int main(){
	scanf("%d %d %d", &n, &t, &m);
	if(n == 1 || t == m){
		printf("0\n");
		return 0;
	}
	for(int i = 1; i < n; i++){
		int u, v;
		scanf("%d %d", &u, &v);
		grafo[u].push_back(v);
		grafo[v].push_back(u);
	}
	dfs(t, 0);
//	printf("oi\n");
	int ans = dp[m];
	m = grafo[m][0];
//	printf("%d\n",m );
	while(m != t){
		//printf("%d\n", m);
		ans += grafo[m].size() - 2;
		m = grafo[m][0];
	}
	printf("%d\n",ans);
}

Compilation message

mousetrap.cpp: In function 'void dfs(int, int)':
mousetrap.cpp:15:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |  for(int i = 0; i < grafo[x].size(); i++){
      |                 ~~^~~~~~~~~~~~~~~~~
mousetrap.cpp:21:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  for(int i = 0 ; i < grafo[x].size(); i++){
      |                  ~~^~~~~~~~~~~~~~~~~
mousetrap.cpp: In function 'int main()':
mousetrap.cpp:33:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   33 |  scanf("%d %d %d", &n, &t, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:40:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   40 |   scanf("%d %d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 15 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 14 ms 23808 KB Output is correct
4 Correct 14 ms 23808 KB Output is correct
5 Correct 14 ms 23808 KB Output is correct
6 Correct 16 ms 23936 KB Output is correct
7 Correct 14 ms 23808 KB Output is correct
8 Correct 15 ms 23808 KB Output is correct
9 Correct 14 ms 23808 KB Output is correct
10 Correct 14 ms 23808 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 414 ms 59000 KB Output is correct
2 Correct 369 ms 55508 KB Output is correct
3 Correct 924 ms 60248 KB Output is correct
4 Correct 437 ms 41976 KB Output is correct
5 Correct 923 ms 60280 KB Output is correct
6 Correct 922 ms 60096 KB Output is correct

Subtask #3
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 15 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 14 ms 23808 KB Output is correct
4 Correct 14 ms 23808 KB Output is correct
5 Correct 14 ms 23808 KB Output is correct
6 Correct 16 ms 23936 KB Output is correct
7 Correct 14 ms 23808 KB Output is correct
8 Correct 15 ms 23808 KB Output is correct
9 Correct 14 ms 23808 KB Output is correct
10 Correct 14 ms 23808 KB Output is correct
11 Incorrect 14 ms 23808 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 15 ms 23808 KB Output is correct
2 Correct 14 ms 23808 KB Output is correct
3 Correct 14 ms 23808 KB Output is correct
4 Correct 14 ms 23808 KB Output is correct
5 Correct 14 ms 23808 KB Output is correct
6 Correct 16 ms 23936 KB Output is correct
7 Correct 14 ms 23808 KB Output is correct
8 Correct 15 ms 23808 KB Output is correct
9 Correct 14 ms 23808 KB Output is correct
10 Correct 14 ms 23808 KB Output is correct
11 Correct 414 ms 59000 KB Output is correct
12 Correct 369 ms 55508 KB Output is correct
13 Correct 924 ms 60248 KB Output is correct
14 Correct 437 ms 41976 KB Output is correct
15 Correct 923 ms 60280 KB Output is correct
16 Correct 922 ms 60096 KB Output is correct
17 Incorrect 14 ms 23808 KB Output isn't correct
18 Halted 0 ms 0 KB -