Monikulmio

#include<iostream>
#include<vector>
#include<queue>

using namespace std;

#define S 102

char c[S][S];

int v[S][S];

int N, M;

struct point
{
  int x;
  int y;
};

void debug()
{
  for (int j = 1; j < N + 1; j++)
  {
    for (int i = 1; i < M + 1; i++)
      cout << c[j][i];
    cout << endl;
  }
}

void draw(int x1, int y1, int x2, int y2)
{
  int dx = x2 - x1;
  int dy = y2 - y1;

  // Pick symbol
  char s = '.';

  if (dx * dy < 0) s = '/';
  else s = '\\';
  if (dx == 0) s = '=';
  if (dy == 0) s = '|';

  // Scale direction
  int m = max(abs(dx), abs(dy));

  dx /= m;
  dy /= m;

  for (int i = 1; i < m; i++)
  {
    x1 += dx; y1 += dy; c[x1][y1] = s;
  }
}

void clearVisited()
{
  for (int j = 0; j < S; j++)
    for (int i = 0; i < S; i++)
      v[i][j] = 0;
}

void bfs(point p, char s)
{
  queue<point> q; q.push(p);

  while (q.size())
  {
    point n = q.front(); q.pop();

    if (v[n.x][n.y] == 1)
      continue;
    
    if (c[n.x][n.y] == '*' || c[n.x][n.y] == '=' || c[n.x][n.y] == '|' || c[n.x][n.y] == '/' || c[n.x][n.y] == '\\')
      continue;
    
    v[n.x][n.y] = 1; c[n.x][n.y] = s;

    if (n.x > 0) q.push({n.x-1,n.y});
    if (n.x < S - 1) q.push({n.x+1,n.y});
    if (n.y > 0) q.push({n.x,n.y-1});
    if (n.y < S - 1) q.push({n.x,n.y+1});
  }
}

int main()
{
  int k; cin >> N >> M >> k;

  for (int j = 0; j < S; j++)
    for (int i = 0; i < S; i++)
      c[i][j] = '.';
  
  vector<point> p(k);

  for (int i = 0; i < k; i++)
  {
    int x, y; cin >> x >> y; p[i] = {x, y}; c[x][y] = '*';
  }

  for (int i = 0; i < k - 1; i++)
  {
    draw(p[i].x, p[i].y, p[i+1].x, p[i+1].y);
  }
  draw(p[k-1].x, p[k-1].y, p[0].x, p[0].y);

  clearVisited();

  bfs({0,0}, 'X');

  for (int j = 0; j < S; j++)
  for (int i = 0; i < S; i++)
  if (c[i][j] == '.')
  {
    bfs({i, j}, '#');
    break;
  }

  clearVisited();

  bfs({0,0}, '.');

  debug();
}

Test 1 (public)

Verdict: ACCEPTED

Test 2 (public)

Verdict: ACCEPTED

Test 3 (public)

Verdict: ACCEPTED

Test 4 (public)

Verdict: ACCEPTED

Test 5 (public)

Verdict: ACCEPTED

Test 6 (public)

Verdict: ACCEPTED

Test 7 (public)

Verdict: ACCEPTED

Test 8 (public)

Verdict: ACCEPTED

Test 9 (public)

Verdict: ACCEPTED

Test 10 (public)

Verdict: ACCEPTED