BUPT-homework/semester3/pset6/7-2-拓扑排序.c

// NEEDS REWORKING
#include <stdio.h>
#include <stdlib.h>
#define SIZE 11

typedef struct listNode {
  char ID;
  struct listNode *next;
} listNode;

typedef struct queue {
  listNode **arr;
  int back;
  int front;
} queue;

listNode *newNode(char ID) {
  listNode *new = malloc(sizeof(listNode));
  new->ID = ID;
  new->next = NULL;

  return new;
}

queue *newQueue() {
  queue *q = malloc(sizeof(queue));
  q->arr = malloc(sizeof(listNode *) * SIZE);
  q->back = 0;
  q->front = 0;
  return q;
}

void appendNode(listNode *node, listNode *new) {
  while (node->next != NULL) {
    node = node->next;
  }
  node->next = new;
}

void push(listNode *li, queue *q) { q->arr[q->back++] = li; }

int isEmpty(queue *q) { return (q->front == q->back); }

listNode *getFront(queue *q) { return q->arr[q->front]; }

void pop(queue *q) {
  if (!isEmpty(q)) {
    q->front++;
  }
}

listNode **makeGraph() {

  listNode **graph = malloc(sizeof(listNode *) * SIZE);

  // initialize graph
  int count = 0;
  graph[count++] = newNode('S');
  for (; count < 10; count++) {
    graph[count] = newNode(count + 'A' - 1);
  }
  graph[count++] = newNode('T');

  appendNode(graph[0], newNode('A'));
  appendNode(graph[0], newNode('D'));
  appendNode(graph[0], newNode('G'));

  appendNode(graph[1], newNode('B'));
  appendNode(graph[1], newNode('E'));

  appendNode(graph[2], newNode('C'));

  appendNode(graph[3], newNode('T'));

  appendNode(graph[4], newNode('A'));
  appendNode(graph[4], newNode('E'));

  appendNode(graph[5], newNode('C'));
  appendNode(graph[5], newNode('F'));
  appendNode(graph[5], newNode('I'));

  appendNode(graph[6], newNode('C'));
  appendNode(graph[6], newNode('T'));

  appendNode(graph[7], newNode('D'));
  appendNode(graph[7], newNode('E'));
  appendNode(graph[7], newNode('H'));

  appendNode(graph[8], newNode('E'));
  appendNode(graph[8], newNode('I'));

  appendNode(graph[9], newNode('F'));
  appendNode(graph[9], newNode('T'));

  return graph;
}

int ch2digit(char ch) {
  if (ch == 'S') {
    return 0;
  } else if (ch == 'T') {
    return 10;
  } else {
    return ch - 'A' + 1;
  }
}

int *getIndegree(listNode **g) {
  int *inDegree = malloc(sizeof(int) * SIZE);
  for (int i = 0; i < SIZE; i++) { // init to 0
    inDegree[i] = 0;
  }

  for (int i = 0; i < SIZE; i++) {
    listNode *ptr = g[i]->next;
    while (ptr != NULL) {
      inDegree[ch2digit(ptr->ID)]++;
      ptr = ptr->next;
    }
  }

  // for (int i = 0; i < SIZE; i++) {
  //   printf("%c: %d\n", g[i]->ID, inDegree[i]);
  // }

  return inDegree;
}

void topoSort(listNode **g) {
  queue *q = newQueue();
  int visited[SIZE] = {};
  int *inDegree = getIndegree(g);

  for (int count = 0; count < SIZE; count++) {

    for (int i = 0; i < SIZE; i++) {
      if (inDegree[i] == 0 && visited[i] == 0) {
        // printf("pushing: %c\n", g[i]->ID);
        push(g[i], q);
        visited[i] = 1;
      }
    }

    listNode *tmp;
    while (!isEmpty(q)) {
      tmp = getFront(q);
      pop(q);
      printf("%c,", tmp->ID);

      tmp = g[ch2digit(tmp->ID)]->next;
      while (tmp != NULL) {
        if (--inDegree[ch2digit(tmp->ID)] == 0 &&
            visited[ch2digit(tmp->ID)] == 0) {
          push(tmp, q);
          visited[ch2digit(tmp->ID)] = 1;
        }
        tmp = tmp->next;
      }
    }
  }
}

void deleteEdge(listNode **g, char src, char dist) {
  listNode *ptr = g[ch2digit(src)];
  while (ptr != NULL && ptr->next != NULL) {
    if (ptr->next->ID == dist) {
      ptr->next = ptr->next->next;
    }
    ptr = ptr->next;
  }
}

int main(void) {
  queue *q = newQueue();
  listNode **g = makeGraph();

  char src, dist;
  scanf("%c,%c", &src, &dist);
  deleteEdge(g, src, dist);

  topoSort(g);

  return 0;
}