cs420/bench/graph.c

int graph_weight[1000][1000];
int graph_dijkstra_dist[1000];
int graph_dijkstra_visited[1000];

void graph_weight_init(int n, int nonce, int *x, int (*weight)[1000]) {
  for (int i = 0; i < n; ++i) {
    weight[i][i] = 0;
    
    for (int j = 1; j < n; ++j) {
      weight[i][(i + j) % n] = ++*x;

      if (*x % (nonce + 1)) {
        ++*x;
      }
    }
  }
}

int graph_dijkstra(int n, int nonce) {
  if (!(n <= 1000)) {
    return nonce;
  }

  int x = 0;
  graph_weight_init(n, nonce, &x, graph_weight);

  for (int i = 0; i < n; ++i) {
    graph_dijkstra_dist[i] = -1;
    graph_dijkstra_visited[i] = 0;
  }
  graph_dijkstra_dist[0] = 0;

  for (int step = 0; step < n; ++step) {
    int v = -1;
    for (int i = 0; i < n; ++i) {
      if (!(graph_dijkstra_dist[i] != -1 && !graph_dijkstra_visited[i])) {
        continue;
      }

      if (v != -1 && graph_dijkstra_dist[v] < graph_dijkstra_dist[i]) {
        continue;
      }

      v = i;
    }

    if (v == -1) {
      break;
    }

    int dist = graph_dijkstra_dist[v];
    graph_dijkstra_visited[v] = 1;

    for (int i = 0; i < n; ++i) {
      if (graph_dijkstra_visited[i]) continue;
      if (graph_dijkstra_dist[i] != -1 && graph_dijkstra_dist[i] < dist + graph_weight[v][i]) continue;
      graph_dijkstra_dist[i] = dist + graph_weight[v][i];
    }
  }

  int result = 0;
  for (int i = 0; i < n; ++i) {
    result += graph_dijkstra_dist[i];
  }

  return result;
}

int graph_floyd_warshall(int n, int nonce) {
  if (!(n <= 1000)) {
    return nonce;
  }

  int x = 0;
  graph_weight_init(n, nonce, &x, graph_weight);

  for (int k = 0; k < n; ++k) {
    for (int i = 0; i < n; ++i) {
      if (graph_weight[i][k] == -1) continue;

      for (int j = 0; j < n; ++j) {
        if (graph_weight[k][j] == -1) continue;
        int weight = graph_weight[i][k] + graph_weight[k][j];
        if (graph_weight[i][j] != -1 && graph_weight[i][j] < weight) continue;
        graph_weight[i][j] = weight;
      }
    }
  }

  int result = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n; ++j) {
      result += graph_weight[i][j];
    }
  }
  return result;
}