c/c++ 图的创建及图的相关函数(链表法）
图的概念
图由点和线组成
知道了图中有多少个点，和哪些点之间有线，就可以把一张图描绘出来
点之间的线，分有方向和无方向
创建图
创建图，实际就是创建出节点，和节点之间的线。
下面的代码实现了上面的图的创建
graph_link.h
#ifndef __graph_link__
#define __graph_link__
#include <stdio.h>
#include <malloc.h>#include <assert.h>
#include <memory.h>
#define default_vertex_size 10#define T char//边的结构typedef struct Edge{
//顶点的下标
int idx; //指向下一个边的指针
struct Edge* link;}Edge;//顶点的结构typedef struct Vertex{
//顶点的值
T data; //边
Edge* adj;
}Vertex;//图的结构typedef struct GraphLink{
int MaxVertices; int NumVertices; int NumEdges;
Vertex* nodeTable;
}GraphLink;
//初始化图void init_graph_link(GraphLink* g);
//显示图void show_graph_link(GraphLink* g);
//插入顶点void insert_vertex(GraphLink* g, T v);
//插入边尾插void insert_edge_tail(GraphLink* g, T v1, T v2);
//插入边头插void insert_edge_head(GraphLink* g, T v1, T v2);
//删除边void remove_edge(GraphLink* g, T v1, T v2);
//删除顶点void remove_vertex(GraphLink* g, T v);
//销毁图void destroy_graph_link(GraphLink* g);
//取得指定顶点的第一个后序顶点int get_first_neighbor(GraphLink* g, T v);
//取得指定顶点v1的临街顶点v2的第一个后序顶点int get_next_neighbor(GraphLink* g, T v1, T v2);#endifgraph_link.c
#include "graph_link.h"//初始化图void init_graph_link(GraphLink* g){
g->MaxVertices = default_vertex_size;
g->NumVertices = g->NumEdges = 0;
g->nodeTable = (Vertex*)malloc(sizeof(Vertex) * g->MaxVertices);
assert(NULL != g->nodeTable); for(int i = 0; i < g->MaxVertices; ++i){
g->nodeTable[i].adj = NULL;
}
}//显示图void show_graph_link(GraphLink* g){
if(NULL == g)return;
for(int i = 0; i < g->NumVertices; ++i){
printf("%d %c->", i, g->nodeTable[i].data);
Edge* p = g->nodeTable[i].adj; while(NULL != p){
printf("%d->", p->idx);
p = p->link;
} printf(" NULL\n");
}
}//插入顶点void insert_vertex(GraphLink* g, T v){
if(g->NumVertices >= g->MaxVertices)return;
g->nodeTable[g->NumVertices++].data = v;
}//查找顶点的indexint getVertexIndex(GraphLink* g, T v){
for(int i = 0; i < g->NumVertices; ++i){
if(v == g->nodeTable[i].data)return i;
} return -1;
}//创建边void buyEdge(Edge** e, int idx){
Edge* p = (Edge*)malloc(sizeof(Edge));
p->idx = idx;
p->link = NULL; if(NULL == *e){
*e = p;
} else{
Edge* tmp = *e; while(tmp->link != NULL){
tmp = tmp->link;
}
tmp->link = p;
}
}//插入边(尾插）void insert_edge_tail(GraphLink* g, T v1, T v2){
int p1 = getVertexIndex(g, v1);
int p2 = getVertexIndex(g, v2);
if(p1 == -1 || p2 == -1)return;
buyEdge(&(g->nodeTable[p1].adj), p2);
g->NumEdges++;
buyEdge(&(g->nodeTable[p2].adj), p1);
g->NumEdges++;
}//插入边(头插）void insert_edge_head(GraphLink* g, T v1, T v2){
int p1 = getVertexIndex(g, v1);
int p2 = getVertexIndex(g, v2);
if(p1 == -1 || p2 == -1)return;
Edge* p = (Edge*)malloc(sizeof(Edge));
p->idx = p2;
p->link = g->nodeTable[p1].adj;
g->nodeTable[p1].adj = p;
p = (Edge*)malloc(sizeof(Edge));
p->idx = p1;
p->link = g->nodeTable[p2].adj;
g->nodeTable[p2].adj = p;
}//删除边int remove_edge_(Edge** p, int i){ if(NULL == *p)return -1;
Edge* f; //判断第一个边是否是目标边
if((*p)->idx == i){ //删除第一条边
f = *p;
*p = (*p)->link; free(f); return 0;
}
Edge* tmp = *p; while(tmp->link != NULL && tmp->link->idx != i){
tmp = tmp->link;
} //没有找到边
if(tmp->link == NULL){ return -1;
} //找到边
else{
f = tmp->link;
tmp->link = tmp->link->link; free(f); return 0;
}
}void remove_edge(GraphLink* g, T v1, T v2){ int p1 = getVertexIndex(g, v1); int p2 = getVertexIndex(g, v2); if(p1 == -1 || p2 == -1)return; int r = remove_edge_(&(g->nodeTable[p1].adj), p2); if(r == 0){
g->NumEdges--;
remove_edge_(&(g->nodeTable[p2].adj), p1);
g->NumEdges--;
}
}//删除顶点void remove_vertex(GraphLink* g, T v){ int p = getVertexIndex(g, v); if(p == -1)return; //删除目标顶点以外的顶点，与目标顶点之间的边
for(int i = 0; i < g->NumVertices; ++i){ if(i == p){ continue;
}else{
remove_edge_(&(g->nodeTable[i].adj), p);
}
} //删除目标顶点行的所有边
Edge* te = g->nodeTable[p].adj;
Edge* tmp; while(te != NULL){
tmp = te;
te = te->link; free(tmp);
} //让被删除顶点那行，指向最后一个顶点那行。
//因为最后一行向上移动了，所以要修改和最后一行有连线的点那行的线的下标。
g->nodeTable[p].data = g->nodeTable[g->NumVertices - 1].data;
g->nodeTable[p].adj = g->nodeTable[g->NumVertices - 1].adj;
tmp = g->nodeTable[p].adj;
Edge* q; while(tmp != NULL){
q = g->nodeTable[tmp->idx].adj; while(q != NULL && q->idx != g->NumVertices - 1){
q = q->link;
}
q->idx = p;
tmp = tmp->link;
}
g->NumVertices--;
}//销毁图void destroy_graph_link(GraphLink* g){ //释放所有边的内存空间
Edge* t = NULL;
Edge* p = NULL; for(int i = 0; i< g->NumVertices; ++i){
t = g->nodeTable[i].adj; while(NULL != t){
p = t;
t = t->link; free(p);
}
} //释放所有顶点的内存空间
free(g->nodeTable);
g->nodeTable = NULL;
g->MaxVertices = g->NumVertices = g->NumEdges = 0;
}//取得指定顶点的第一个后序顶点int get_first_neighbor(GraphLink* g, T v){ int i = getVertexIndex(g, v); if (-1 == i)return -1;
Edge* p = g->nodeTable[i].adj; if(NULL != p) return p->idx; else
return -1;
}//取得指定顶点v1的临街顶点v2的第一个后序顶点int get_next_neighbor(GraphLink* g, T ve1, T ve2){ int v1 = getVertexIndex(g, ve1); int v2 = getVertexIndex(g, ve2); if(v1 == -1 || v2 == -1)return -1;
Edge* t = g->nodeTable[v1].adj; while(t != NULL && t->idx != v2){
t = t->link;
} if(NULL != t && t->link != NULL){ return t->link->idx;
} return -1;
}graph_linkmain.c
#include "graph_link.h"int main(){
GraphLink gl; //初始化图
init_graph_link(&gl); //插入节点
insert_vertex(&gl, 'A');
insert_vertex(&gl, 'B');
insert_vertex(&gl, 'C');
insert_vertex(&gl, 'D');
insert_vertex(&gl, 'E'); //显示图
//show_graph_link(&gl);
//插入边(尾插)
/*
insert_edge_tail(&gl, 'A', 'B');
insert_edge_tail(&gl, 'A', 'D');
insert_edge_tail(&gl, 'B', 'C');
insert_edge_tail(&gl, 'B', 'E');
insert_edge_tail(&gl, 'C', 'D');
insert_edge_tail(&gl, 'C', 'E');
*/
//插入边(头插)
///*
insert_edge_head(&gl, 'A', 'B');
insert_edge_head(&gl, 'A', 'D');
insert_edge_head(&gl, 'B', 'C');
insert_edge_head(&gl, 'B', 'E');
insert_edge_head(&gl, 'C', 'D');
insert_edge_head(&gl, 'C', 'E'); //*/
//显示图
show_graph_link(&gl); printf("\n"); //删除边
remove_edge(&gl, 'A', 'D'); //显示图
show_graph_link(&gl); printf("\n"); //删除顶点
remove_vertex(&gl, 'C'); //显示图
show_graph_link(&gl); //临街顶点的下标
int v = get_first_neighbor(&gl, 'B');
printf("%d\n", v);
v = get_next_neighbor(&gl, 'B', 'A');
printf("%d\n", v); //销毁图
destroy_graph_link(&gl);
}作者：小石王
原文链接：https://www.cnblogs.com/xiaoshiwang/p/9394347.html