oj.uz

Submission #97143

# Submission time Handle Problem Language Result Execution time Memory
97143 2019-02-14T04:37:37 Z dndhk Pipes (CEOI15_pipes) C++14
100 / 100
 1563 ms 8376 KB 
#include <iostream>
#include <vector>
#include <stdio.h>
#include <algorithm>

#define MAX_N 100000

using namespace std;

int N, M;
pair<int, int> gp[MAX_N*4+1];
int sz = 0;
int g1[MAX_N+1], g2[MAX_N+1];
int up[MAX_N+1], lv[MAX_N+1], p[MAX_N+1];

int find_g1(int x){
	if(x==g1[x])	return x;
	return g1[x] = find_g1(g1[x]);
}

int find_g2(int x){
	if(x==g2[x])	return x;
	return g2[x] = find_g2(g2[x]);
}

int s, e, m;

void dfs(int x){
	bool tf = true;
	up[x] = lv[x];
	s = 0, e = sz-1;
	while(s<e){
		m = (s+e)/2;
		if(gp[m].first<x) s = m+1;
		else	e = m;
	}
	for(int i=s; i<sz; i++){
		if(gp[i].first!=x)	break;
		if(gp[i].second==p[x] && tf){
			tf = false; continue;
		}	
		if(lv[gp[i].second]!=0){
			up[x] = min(up[x], lv[gp[i].second]);
		}else{
			p[gp[i].second] = x;
			lv[gp[i].second] = lv[x]+1;
			dfs(gp[i].second);
			if(up[gp[i].second]>lv[x])	printf("%d %d\n", gp[i].second, x);
			up[x] = min(up[x], up[gp[i].second]);
		}
	}
}

int main(){
	scanf("%d %d", &N, &M);
	for(int i=1; i<=N; i++)	g1[i] = g2[i] = i;
	int a, b;
	while(M--){
		scanf("%d%d", &a, &b);
		if(find_g1(a)!=find_g1(b)){
			gp[sz++] = {a, b}; gp[sz++] = {b, a};
			a = find_g1(a); b = find_g1(b);
			g1[a] = b;
		}
		else if(find_g2(a)!=find_g2(b)){
			gp[sz++] = {a, b}; gp[sz++] = {b, a};
			a = find_g2(a); b = find_g2(b);
			g2[a] = b;
		}
	}sort(gp, gp+sz);
	for(int i=1; i<=N; i++){
		if(lv[i]==0){
			lv[i] = 1;
			dfs(i);
		}
	}
	return 0;
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:55:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &N, &M);
  ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:59:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &a, &b);
   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 384 KB Output is correct
2 Correct 2 ms 384 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 636 KB Output is correct
2 Correct 6 ms 512 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 117 ms 636 KB Output is correct
2 Correct 116 ms 632 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 207 ms 1144 KB Output is correct
2 Correct 242 ms 888 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 343 ms 2172 KB Output is correct
2 Correct 292 ms 2204 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 535 ms 6008 KB Output is correct
2 Correct 443 ms 4188 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 753 ms 6928 KB Output is correct
2 Correct 741 ms 5124 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1029 ms 8316 KB Output is correct
2 Correct 985 ms 6008 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1242 ms 8376 KB Output is correct
2 Correct 1211 ms 5780 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1563 ms 7868 KB Output is correct
2 Correct 1483 ms 6272 KB Output is correct