Submission #302167

#	Time	Username	Problem	Language	Result	Execution time	Memory
302167		radaiosm7	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	264 ms	22264 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;
int par[1005];
int depth[1005];
vector<int> teams[1005];
vector<int> cycle;

int FindPre(int x) {
  if (par[x] == x) {
    return x;
  }  else {
    par[x] = FindPre(par[x]);
    return par[x];
  }
}

bool IsSame(int x, int y) {
  if (FindPre(x) == FindPre(y)) {
    return true;
  }

  else {
    return false;
  }
}

void Union(int x, int y) {
  int PX = FindPre(x);
  int PY = FindPre(y);

  if (depth[PX] > depth[PY]) {
    par[PY] = PX;
  }

  else if (depth[PX] < depth[PY]) {
    par[PX] = PY;
  }

  else {
    par[PY] = PX;
    depth[PX]++;
  }
}


int construct(vector<vector<int>> p) {
  int n = p.size();
  vector<vector<int>> ans(n, vector<int>(n, 0));

  for (int i=0; i < n; i++) {
    par[i] = i;
    depth[i] = 1;
  }

  for (int i=0; i < n; i++) {
    for (int j=0; j < n; j++) {
      if (p[i][j] != 0) {
        Union(i,j);
      }

      if (p[i][j] == 3) {
        return 0;
      }
    }
  }

  for (int i=0; i < n; i++) {
    for (int j=0; j < n; j++) {
      if (p[i][j] == 0 && IsSame(i,j)) {
        return 0;
      }
    }
  }



  for (int i=0; i < n; i++) {
      teams[FindPre(i)].push_back(i);
  }

  for (int i=0; i < n; i++) {
    par[i] = i;
    depth[i] = 1;
  }

  for (int gr=0; gr < n; gr++) {
    if ((int)teams[gr].size() == 0) {
      continue;
    }

    for (int i = 0; i < (int)teams[gr].size(); i++) {
        for (int j = i+1; j < (int)teams[gr].size(); j++) {
            if (p[teams[gr][i]][teams[gr][j]] == 1) {
              Union(teams[gr][i], teams[gr][j]);
            }
        }
    }

    for (int i = 0; i < (int)teams[gr].size(); i++) {
        for (int j = i+1; j < (int)teams[gr].size(); j++) {
            if (p[teams[gr][i]][teams[gr][j]] == 2 && IsSame(teams[gr][i], teams[gr][j])) {
              return 0;
            }
        }
    }

    cycle.clear();

    for (auto curr : teams[gr]) {
      if (par[curr] == curr) {
        cycle.push_back(curr);
      }

      else {
        ans[curr][par[curr]] = ans[par[curr]][curr] = 1;
      }
    }

    if ((int)cycle.size() == 2) {
      return 0;
    }

    else if ((int)cycle.size() == 1) {
      continue;
    }

    else {
      for (int i=0; i+1 < (int)cycle.size(); i++) {
        ans[cycle[i]][cycle[i+1]] = ans[cycle[i+1]][cycle[i]] = 1;
      }

      ans[cycle[0]][cycle.back()] = ans[cycle.back()][cycle[0]] = 1;
    }
  }

  build(ans);
  return 1;
}

• Subtask 1: 11 / 11
• Subtask 2: 10 / 10
• Subtask 3: 19 / 19
• Subtask 4: 35 / 35
• Subtask 5: 21 / 21
• Subtask 6: 4 / 4