#include <iostream>
#include <vector>
#include <cassert>
#include <set>
using ll = long long;
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MAX(a, b) (((a) < (b)) ? (b) : (a))
int const nmax = 100000;
int const sigma = 10;
int mult[1 + nmax], acc[1 + nmax], sz[1 + nmax];
int level[1 + nmax];
std::vector<int> g[1 + nmax];
std::set<std::pair<int,int>> answer;
int far[1 + sigma][1 + nmax];
int jump(int gala) {
if(mult[gala] != gala)
mult[gala] = jump(mult[gala]);
return mult[gala];
}
void initialize(int n) {
for(int i = 1; i <= n; i++)
mult[i] = i;
for(int i = 1;i <= n; i++)
sz[i] = 1;
}
bool isconnected(int gala, int galb) {
return jump(gala) == jump(galb);
}
void clean(int node, int parent) {
for(int h = 0; h < g[node].size(); h++) {
int to = g[node][h];
if(to != parent) {
clean(to, node);
acc[node] += acc[to];
}
}
if(0 < acc[node]) {
answer.erase({node, parent});
answer.erase({parent, node});
}
}
void refresh(int node, int parent) {
acc[node] = 0;
level[node] = level[parent] + 1;
far[0][node] = parent;
for(int h = 1; h <= sigma; h++)
far[h][node] = far[h - 1][far[h - 1][far[h - 1][far[h - 1][node]]]];
for(int h = 0; h < g[node].size(); h++) {
int to = g[node][h];
if(to != parent)
refresh(to, node);
}
}
bool unite(int x, int y) {
int gala = jump(x);
int galb = jump(y);
if(gala == galb)
return false;
else {
if(sz[galb] < sz[gala]){
std::swap(x, y);
std::swap(gala, galb);
}
clean(gala, 0);
g[x].push_back(y);
g[y].push_back(x);
refresh(x, y);
mult[gala] = galb;
sz[galb] += sz[gala];
answer.insert({x, y});
return true;
}
}
int getlca(int x, int y) {
if(level[x] < level[y])
std::swap(x, y);
for(int h = sigma; 0 <= h; h--)
while(level[y] <= level[x] - (1 << (2 * h)))
x = far[h][x];
if(x == y)
return x;
for(int h = sigma; 0 <= h; h--)
while(far[h][x] != far[h][y]) {
x = far[h][x];
y = far[h][y];
}
return far[0][x];
}
void add_chain(int x, int y) {
acc[getlca(x, y)] -= 2;
acc[x]++;
acc[y]++;
}
int main() {
std::ios::sync_with_stdio(0);
std::cin.tie(0);
int n, m;
std::cin >> n >> m;
initialize(n);
for(int i = 1;i <= m; i++) {
int x, y;
std::cin >> x >> y;
if(unite(x, y) == false)
add_chain(x, y);
}
for(int i = 1;i <= n; i++)
if(mult[i] == i)
clean(i, 0);
for(std::set<std::pair<int,int>>::iterator it = answer.begin(); it != answer.end(); it++)
std::cout << it->first << " " << it->second << '\n';
return 0;
}
Compilation message
pipes.cpp: In function 'void clean(int, int)':
pipes.cpp:36:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | for(int h = 0; h < g[node].size(); h++) {
| ~~^~~~~~~~~~~~~~~~
pipes.cpp: In function 'void refresh(int, int)':
pipes.cpp:56:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
56 | for(int h = 0; h < g[node].size(); h++) {
| ~~^~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
2816 KB |
Output is correct |
2 |
Correct |
2 ms |
2688 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
3328 KB |
Output is correct |
2 |
Correct |
10 ms |
3328 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
187 ms |
3200 KB |
Output is correct |
2 |
Correct |
175 ms |
3320 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
372 ms |
4216 KB |
Output is correct |
2 |
Correct |
416 ms |
4088 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
678 ms |
6136 KB |
Output is correct |
2 |
Correct |
576 ms |
6776 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1148 ms |
12280 KB |
Output is correct |
2 |
Correct |
1058 ms |
12336 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1911 ms |
13776 KB |
Output is correct |
2 |
Runtime error |
1706 ms |
47184 KB |
Memory limit exceeded |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
2769 ms |
16572 KB |
Memory limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3679 ms |
16324 KB |
Output is correct |
2 |
Runtime error |
3657 ms |
65536 KB |
Memory limit exceeded |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4230 ms |
15608 KB |
Output is correct |
2 |
Runtime error |
3702 ms |
65536 KB |
Memory limit exceeded |