oj.uz

Submission #682112

# Submission time Handle Problem Language Result Execution time Memory
682112 2023-01-15T19:21:52 Z MilosMilutinovic Pipes (CEOI15_pipes) C++14
100 / 100
 2991 ms 13300 KB 
/**
 *    author:  wxhtzdy
 *    created: 15.01.2023 19:07:48
**/
#include <bits/stdc++.h>

using namespace std;

const int MAX = 100000;
const int L = 16;

int n, m;
vector<int> g[MAX];
int f[MAX];
int i;
int j;
int par[MAX];
int dep[MAX];
int jump[MAX][L];
int u;
int v;
int pu;
int pv;
int w;

void SolveFirstSubtask() {
  for (i = 0; i < m; i++) {
    cin >> jump[i][0] >> jump[i][1];
    --jump[i][0];
    --jump[i][1];
  }           
  function<int(int)> getRoot = [&](int x) {
    return f[x] == x ? x : f[x] = getRoot(f[x]);
  };
  for (i = 0; i < m; i++) {
    for (j = 0; j < n; j++) f[j] = j;
    for (j = 0; j < m; j++) {
      if (i != j) {
        f[getRoot(jump[j][0])] = getRoot(jump[j][1]);
      }
    }
    if (getRoot(jump[i][0]) != getRoot(jump[i][1])) {
      cout << jump[i][0] + 1 << " " << jump[i][1] + 1 << '\n';
    }
  }
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);  
  cin >> n >> m;
  if (n <= 100 && m <= 200) {
    SolveFirstSubtask();
    return 0;
  }
  for (i = 0; i < n; i++) {
    par[i] = -1;
  }
  function<int(int)> get = [&](int x) {
    return par[x] < 0 ? x : par[x] = get(par[x]);
  };
  for (i = 0; i < n; i++) {
    for (j = 0; j < L; j++) {
      jump[i][j] = i;
    }
  }
  function<void(int, int)> Dfs = [&](int v, int pr) {
    dep[v] = dep[pr] + 1;   
    jump[v][0] = pr;
    for (j = 1; j < L; j++) {
      jump[v][j] = jump[jump[v][j - 1]][j - 1];
    }    
    for (int u : g[v]) {
      if (u != pr) {
        Dfs(u, v);
      }
    }
  }; 
  auto LCA = [&](int u, int v) {
    if (dep[u] > dep[v]) {
      swap(u, v);
    }
    for (j = L - 1; j >= 0; j--) {
      if (dep[jump[v][j]] >= dep[u]) {
        v = jump[v][j];
      }
    }
    if (u == v) {
      return u;
    }
    for (j = L - 1; j >= 0; j--) {
      if (jump[u][j] != jump[v][j]) {
        u = jump[u][j];
        v = jump[v][j];
      }
    }
    return jump[u][0];
  };
  for (i = 0; i < m; i++) {
    cin >> u >> v;
    --u; --v;
    if (get(u) != get(v)) {
      pu = get(u);
      pv = get(v);
      if (par[pu] > par[pv]) {
        swap(pu, pv);
        swap(u, v);        
      }
      Dfs(v, u);
      g[u].push_back(v);
      g[v].push_back(u);
      par[pu] += par[pv];
      par[pv] = pu;
    } else {
      w = LCA(u, v);
      f[u] += 1;
      f[v] += 1;
      f[w] -= 2;  
    }
  }
  function<void(int, int)> Solve = [&](int v, int pr) {
    for (int u : g[v]) {
      if (u != pr) {
        Solve(u, v);
        f[v] += f[u];
      }
    }
    if (f[v] == 0 && pr != -1) {
      cout << v + 1 << " " << pr + 1 << '\n';
    }
  };
  for (i = 0; i < n; i++) {
    if (get(i) == i) {
      Solve(i, -1);
    }
  }
  return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 3164 KB Output is correct
2 Correct 6 ms 3156 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 189 ms 3028 KB Output is correct
2 Correct 179 ms 3032 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 333 ms 3668 KB Output is correct
2 Correct 399 ms 3672 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 583 ms 5180 KB Output is correct
2 Correct 515 ms 5824 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 847 ms 10056 KB Output is correct
2 Correct 719 ms 9932 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1374 ms 11164 KB Output is correct
2 Correct 1186 ms 11224 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1995 ms 13124 KB Output is correct
2 Correct 1847 ms 13300 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2503 ms 13244 KB Output is correct
2 Correct 2536 ms 13272 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2991 ms 12600 KB Output is correct
2 Correct 2567 ms 13228 KB Output is correct