DFS&&BFS ---C ----complete

//
//  main.cpp
//  BFS_cursive
//
//  Created by 韩雪滢 on 10/23/16.
//  Copyright © 2016 韩雪滢. All rights reserved.
//


#include <stdio.h>
#include <stdlib.h>

#define NUM_VERTEX 10

struct Vertex {
    char name;
    int mark;
    struct Node* list;
};
struct Node {
    struct Vertex* vertex;
    struct Node* next;
};
struct Queue {
};
typedef struct Vertex Vertex;
typedef struct Node Node;

// creates a new vertex and return pointer to it
Vertex* new_vertex(char name) {
    Vertex* vertex = (Vertex*)malloc(sizeof(Vertex));
    vertex->name = name;
    vertex->list = 0;
    return vertex;
}

// connect the vertex a to vertex b
// by adding b to a's linked list!
void do_connect(Vertex* a, Vertex* b) {
    Node* node = (Node*)malloc(sizeof(Node));
    node->vertex = b;
    node->next = a->list;
    a->list = node;
}

// connects a to b and b to a
void connect(Vertex* a, Vertex* b) {
    do_connect (a, b);
    do_connect (b, a);
}

// visit function
void visit(Vertex* vertex) {
    printf ("\n%5d. %c", vertex->mark, vertex->name);
}

// do a depth first search
void do_dfs(Vertex *vertex, int* count) {
    Node* p = vertex->list;
    vertex->mark = ++(*count);
    visit (vertex);
    while (p != 0) {
        if (!p->vertex->mark) {
            do_dfs (p->vertex, count);
        }
        p = p->next;
    }
}
void dfs(Vertex *graph[]) {
    int i;
    int count = 0;
    // set all to unvisited
    for (i = 0; i < NUM_VERTEX; i ++) {
        graph[i]->mark = 0;
    }
    // each vertex dfs it
    for (i = 0; i < NUM_VERTEX; i ++) {
        if (graph[i]->mark == 0) {
            do_dfs (graph[i], &count);
        }
    }
}

// breadth first search
void do_bfs(Vertex *vertex, int* count) {
    Node *initialQueue, *front, *rear, *p, *temp;
    Vertex *w;
    // count = count + 1, mark vertex with count
    vertex->mark = ++(*count);
    visit (vertex);
    // initialize a queue, and initialize with vertex.
    initialQueue = (Node*)malloc(sizeof(Node));
    initialQueue->vertex = vertex;
    initialQueue->next = 0;
    front = initialQueue;
    rear  = initialQueue;
    // while queue is not empty
    while (front != 0) {
        // for vertyex w in V adjacent to the front vertex
        p = front->vertex->list;
        while (p != 0) {
            w = p->vertex;
            // if w is marked with 0
            if (w->mark == 0) {
                Node* nextQueue;
                // count = count + 1, mark w with count
                w->mark = ++(*count);
                visit (w);
                // add w to queue
                nextQueue = (Node*)malloc(sizeof(Node));
                nextQueue->vertex = w;
                nextQueue->next = 0;
                rear->next = nextQueue;
                rear = nextQueue;
            }
            p = p->next;
        }
        // remove front vertex from queue
        temp = front;
        front = front->next;
        free (temp);
    }
}
void bfs(Vertex *graph[]) {
    int i;
    int count = 0;
    // set all to unvisited
    for (i = 0; i < NUM_VERTEX; i ++) {
        graph[i]->mark = 0;
    }
    // each vertex bfs it
    for (i = 0; i < NUM_VERTEX; i ++) {
        if (graph[i]->mark == 0) {
            do_bfs (graph[i], &count);
        }
    }
}

// main function
int main() {
    
    // create a adjacency list
    Vertex *graph[NUM_VERTEX] = {
        new_vertex('A'), //[0]
        new_vertex('B'), //[1]
        new_vertex('C'), //[2]
        new_vertex('D'), //[3]
        new_vertex('E'), //[4]
        new_vertex('F'), //[5]
        new_vertex('G'), //[6]
        new_vertex('H'), //[7]
        new_vertex('I'), //[8]
        new_vertex('J')  //[9]
    };
    
    // connect the vertices
    connect(graph[0], graph[2]);
    connect(graph[0], graph[3]);
    connect(graph[0], graph[4]);
    connect(graph[1], graph[4]);
    connect(graph[1], graph[5]);
    connect(graph[2], graph[3]);
    connect(graph[2], graph[5]);
    connect(graph[4], graph[5]);
    connect(graph[6], graph[7]);
    connect(graph[6], graph[9]);
    connect(graph[7], graph[8]);
    connect(graph[8], graph[9]);
    
    // depth first search
    printf ("DFS: ");
    dfs (graph);
    
    // breadth first search
    printf ("\n\n");
    printf ("BFS: ");
    bfs (graph);
    
    printf ("\n\nAnd that's it!!");
    getchar ();
    
}