C++ 图的遍历

图的邻接表存储结构的类型声明

//边结点结构类型
struct ANode {
int adjvex;     //边的终点位置
ANode* nextarc; //指向表头结点下一条邻接的边
int info;       //该边的相关信息，对于带权图可存放权值
};
//邻接表头节点类型
struct VNode {
char info; //结点信息
ANode* firstarc; //指向第一条邻接的边
};
//图的邻接表类型
struct AGraph {
vector<VNode*> adjlist; //所有表头组成的数组
int n,e; //结点个数，边条数
};

根据图的邻接矩阵生成图的邻接表

//------生成图的邻接表算法------
void createAdj(AGraph* &G, vector<vector<int> > A, int n) {
//由数组A生成邻接表
ANode *p;
G = new AGraph();
G->n = n;
G->e = 0;
for(int i=0;i<n;i++){
VNode *vnode = new VNode();
vnode->firstarc = NULL;
G->adjlist.push_back(vnode);
}
for(int j=0;j<n;j++) {
for(int k=n-1;k>=0;k--) {
if(A[j][k]!=0) {
p = new ANode();
p->adjvex = k;
p->nextarc = G->adjlist[j]->firstarc;
G->adjlist[j]->firstarc = p;
G->e++;
}
}
}
}

//------输出图的邻接表算法------
void dispAdj(AGraph *G) {
ANode* p;
for(int i=0;i<G->n;i++) {
cout<<i<<"->";
p = G->adjlist[i]->firstarc;
while(p) {
cout<<p->adjvex<<"->";
p = p->nextarc;
}
cout<<"NULL"<<endl;
}
}

深度优先遍历（Depth-First-Search）

//深度优先遍历
void DFS(AGraph *G, int v) {
ANode *p;
visited[v] = 1;
cout<<v<<" ";
p = G->adjlist[v]->firstarc;
while(p) {
if(!visited[p->adjvex])
DFS(G,p->adjvex);
p = p->nextarc;
}
}

广度优先遍历（Breadth-First-Search）

//广度优先遍历
void BFS(AGraph* G,int v) {
ANode *p;
queue<int> qu;
vector<int> flag(G->n);
int w;
cout<<v<<" ";
flag[v]=1;
qu.push(v);
while(!qu.empty()) {
w = qu.front();
qu.pop();
p = G->adjlist[w]->firstarc;
while(p) {
if(!flag[p->adjvex]) {
cout<<p->adjvex<<" ";
flag[p->adjvex] = 1;
qu.push(p->adjvex);
}
p = p->nextarc;
}
}
cout<<endl;
}

完整代码

#include<iostream>
#include<vector>
#include<queue>
using namespace std;
const int num = 10;
vector<int> visited(num);
//图的邻接表存储结构的类型声明------Begin------
//边结点结构类型
struct ANode {
int adjvex;     //边的终点位置
ANode* nextarc; //指向表头结点下一条邻接的边
int info;       //该边的相关信息，对于带权图可存放权值
};
//邻接表头节点类型
struct VNode {
char info; //结点信息
ANode* firstarc; //指向第一条邻接的边
};
//图的邻接表类型
struct AGraph {
vector<VNode*> adjlist; //所有表头组成的数组
int n,e; //结点个数，边条数
};
//邻接表存储结构类型声明------END------

//------生成图的邻接表算法------
void createAdj(AGraph* &G, vector<vector<int> > A, int n) {
//由数组A生成邻接表
ANode *p;
G = new AGraph();
G->n = n;
G->e = 0;
for(int i=0;i<n;i++){
VNode *vnode = new VNode();
vnode->firstarc = NULL;
G->adjlist.push_back(vnode);
}
for(int j=0;j<n;j++) {
for(int k=n-1;k>=0;k--) {
if(A[j][k]!=0) {
p = new ANode();
p->adjvex = k;
p->nextarc = G->adjlist[j]->firstarc;
G->adjlist[j]->firstarc = p;
G->e++;
}
}
}
}

//------输出图的邻接表算法------
void dispAdj(AGraph *G) {
ANode* p;
for(int i=0;i<G->n;i++) {
cout<<i<<"->";
p = G->adjlist[i]->firstarc;
while(p) {
cout<<p->adjvex<<"->";
p = p->nextarc;
}
cout<<"NULL"<<endl;
}
}

//深度优先遍历
void DFS(AGraph *G, int v) {
ANode *p;
visited[v] = 1;
cout<<v<<" ";
p = G->adjlist[v]->firstarc;
while(p) {
if(!visited[p->adjvex])
DFS(G,p->adjvex);
p = p->nextarc;
}
}

//广度优先遍历
void BFS(AGraph* G,int v) {
ANode *p;
queue<int> qu;
vector<int> flag(G->n);
int w;
cout<<v<<" ";
flag[v]=1;
qu.push(v);
while(!qu.empty()) {
w = qu.front();
qu.pop();
p = G->adjlist[w]->firstarc;
while(p) {
if(!flag[p->adjvex]) {
cout<<p->adjvex<<" ";
flag[p->adjvex] = 1;
qu.push(p->adjvex);
}
p = p->nextarc;
}
}
cout<<endl;
}

//测试用例
int main() {
int a[] = {0,1,0,1,0};
int b[] = {0,0,1,1,0};
int c[] = {0,0,0,1,1};
int d[] = {0,0,0,0,0};
int e[] = {1,0,0,1,0};
vector<vector<int> > graph;
vector<int> A(a,a+5);
vector<int> B(b,b+5);
vector<int> C(c,c+5);
vector<int> D(d,d+5);
vector<int> E(e,e+5);

graph.push_back(A);
graph.push_back(B);
graph.push_back(C);
graph.push_back(D);
graph.push_back(E);

AGraph* G;
int n=5;
cout<<"构造图的邻接表："<<endl;
createAdj(G,graph,n);
cout<<"输出图的邻接表:"<<endl;
dispAdj(G);

DFS(G,0);
cout<<endl;
BFS(G,0);
return 0;
}