优化这段代码，并写出来typedef struct ArcNode { int adjvex; struct ArcNode *nextarc; }ArcNode; typedef struct VNode { VertexType data; ArcNode *firstarc; }VNode, AdjList; typedef struct { AdjList vertices[MVNum]; int vexnum, arcnum; }ALGraph; void CreateUDG(ALGraph &G) { cout << "请输入顶点数和边数：\n"; cin>>G.vexnum>>G.arcnum; for(int i=0; i<G.vexnum; ++i) { cout << "请输入顶点信息：\n"; cin>> G.vertices[i].data; G.vertices[i].firstarc=NULL; } for(int k = 0; k<G.arcnum;++k) { int j; ArcNode *p1,*p2; cout<<"请输入每条边对应的两个顶点的序号：\n"; cin>>i>>j; p1=new ArcNode; p1->adjvex=j; p1->nextarc= G.vertices[i].firstarc; G.vertices[i].firstarc=p1; p2=new ArcNode; p2->adjvex=i; p2->nextarc= G.vertices[j].firstarc; G.vertices[j].firstarc=p2; } } void DFS(ALGraph G, int v) { //图G为邻接表类型 cout<<v; visited[v] = true; //访问第v个顶点 p= G.vertices[v].firstarc; //p指向v的边链表的第一个边结点 while(p!=NULL) //边结点非空 { w=p->adjvex; //表示w是v的邻接点 if(!visited[w]) DFS(G, w); //如果w未访问，则递归调用DFS p=p->nextarc; //p指向下一个边结点 } }

优化后的代码如下：

#include <iostream>
#include <cstring>
using namespace std;

const int MVNum = 100;

typedef int VertexType;

struct ArcNode {
    int adjvex;
    struct ArcNode* nextarc;
};

struct VNode {
    VertexType data;
    ArcNode* firstarc;
};

typedef VNode AdjList[MVNum];

struct ALGraph {
    AdjList vertices;
    int vexnum, arcnum;
};

void InputVertex(ALGraph& G) {
    for (int i = 0; i < G.vexnum; ++i) {
        cout << "请输入顶点信息：\n";
        cin >> G.vertices[i].data;
        G.vertices[i].firstarc = nullptr;
    }
}

void InputEdge(ALGraph& G) {
    for (int k = 0; k < G.arcnum; ++k) {
        int i, j;
        ArcNode* p1, * p2;
        cout << "请输入每条边对应的两个顶点的序号：\n";
        cin >> i >> j;
        p1 = new ArcNode;
        p1->adjvex = j;
        p1->nextarc = G.vertices[i].firstarc;
        G.vertices[i].firstarc = p1;
        p2 = new ArcNode;
        p2->adjvex = i;
        p2->nextarc = G.vertices[j].firstarc;
        G.vertices[j].firstarc = p2;
    }
}

void CreateUDG(ALGraph& G) {
    cout << "请输入顶点数和边数：\n";
    cin >> G.vexnum >> G.arcnum;
    InputVertex(G);
    InputEdge(G);
}

bool visited[MVNum];

void DFS(ALGraph G, int v) {
    cout << v;
    visited[v] = true;
    ArcNode* p = G.vertices[v].firstarc;
    while (p != nullptr) {
        int w = p->adjvex;
        if (!visited[w]) {
            DFS(G, w);
        }
        p = p->nextarc;
    }
}

int main() {
    memset(visited, false, sizeof(visited));
    ALGraph G;
    CreateUDG(G);
    DFS(G, 0);
    return 0;
}