제출 #981004

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
981004		kilkuwu	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	171 ms	24500 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>

struct DSU {
  std::vector<int> e;

  DSU(int n) : e(n, -1) {}

  int find(int u) {
    return e[u] < 0 ? u : e[u] = find(e[u]);
  }
  
  bool merge(int u, int v) {
    u = find(u), v = find(v);
    if (u == v) return false;
    if (e[u] > e[v]) std::swap(u, v);
    e[u] += e[v];
    e[v] = u;
    return true;
  } 

  bool same(int u, int v) {
    return find(u) == find(v);
  }
  
  int size(int u) {
    return -e[find(u)];
  }
};

int construct(std::vector<std::vector<int>> p) {
  int n = p.size();

  DSU dsu(n);

  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      if (p[i][j] == 3) return false;
      if (p[i][j] != 0) {
        dsu.merge(i, j);
      }
    }
  }

  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      if (!p[i][j] && dsu.same(i, j)) return false;
    }
  }

  // now we have all the tplt we need 

  // now what can we do ? 
  // each tplt has only one fucking cycle

  std::vector<std::vector<int>> comps(n);
  for (int i = 0; i < n; i++) {
    comps[dsu.find(i)].push_back(i);
  }

  // they must have connected to each other 

  std::vector<std::vector<int>> b(n, std::vector<int>(n));

  DSU lmao(n);

  std::vector<std::pair<int, int>> edges;

  auto add_edge = [&](int u, int v) -> void {
    b[u][v] = b[v][u] = 1;
  };

  for (int c = 0; c < n; c++) {
    if (comps[c].empty()) continue;

    std::map<std::vector<int>, std::vector<int>> mp;

    for (int u : comps[c]) {
      std::vector<int> key;
      for (int j = 0; j < n; j++) {
        if (p[u][j] == 2) {
          key.push_back(j);
        }
      }
      mp[key].push_back(u);
    }

    std::vector<int> rep;

    for (auto& [key, val] : mp) {
      int total = key.size() + val.size(); 
      if (total != (int) comps[c].size()) {
        return false; 
      }
      for (int i = 0; i + 1 < (int) val.size(); i++) {
        add_edge(val[i], val[i + 1]);
      }
      rep.push_back(val[0]);
    }

    if (rep.size() == 2) {
      // we cannot do a cycle with two 
      return false;
    }
    if (rep.size() > 2) {
      for (int i = 0; i < (int)rep.size(); i++) {
        add_edge(rep[i], rep[(i + 1) % rep.size()]);
      }
    }
  }

  build(b);
	return 1;
}


#ifdef LOCAL
#include <vector>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <string>

static int n;
static std::vector<std::vector<int>> p;
static std::vector<std::vector<int>> b;
static bool called = false;

static void check(bool cond, std::string message) {
    if (!cond) {
        printf("%s\n", message.c_str());
        fclose(stdout);
        exit(0);
    }
}

void build(std::vector<std::vector<int>> _b) {
    check(!called, "build is called more than once");
    called = true;
    check((int)_b.size() == n, "Invalid number of rows in b");
    for (int i = 0; i < n; i++) {
        check((int)_b[i].size() == n, "Invalid number of columns in b");
    }
    b = _b;
}

int main() {
    assert(scanf("%d", &n) == 1);
    
    p.resize(n);
    for (int i = 0; i < n; i++) {
        p[i].resize(n);
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            assert(scanf("%d", &p[i][j]) == 1);
        }
    }
    fclose(stdin);

    int possible = construct(p);

    check(possible == 0 || possible == 1, "Invalid return value of construct");
    if (possible == 1) {
        check(called, "construct returned 1 without calling build");
    } else {
        check(!called, "construct called build but returned 0");
    }

    printf("%d\n", possible);
    if (possible == 1) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                if (j) {
                    printf(" ");
                }
                printf("%d", b[i][j]);
            }
            printf("\n");
        }
    }
    fclose(stdout);
}
#endif

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