제출 #682112

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
682112		MilosMilutinovic	Pipes (CEOI15_pipes)	C++14	100 / 100	2991 ms	13300 KiB

pipes

/**
 *    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 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10