BJFUOJ-280

基于邻接表的边的删除

#include<iostream>
using namespace std;
#define maxsize 100
typedef struct ArcNode {
	int val;
	ArcNode* next;
	ArcNode() :val(0), next(nullptr) {}
	ArcNode(int x) :val(x), next(nullptr) {}
}ArcNode;

typedef struct VexNode {
	int data;
	ArcNode* first;
	VexNode() :data(0), first(nullptr) {}
}VexNode;
typedef struct {
	VexNode vexs[maxsize];
	int VexNum, ArcNum;
}ALGraph;


void addArc(ALGraph& G, int n1, int n2) {
	ArcNode* p1 = new ArcNode(n1);
	ArcNode* p2 = new ArcNode(n2);
	int index1 = 0;
	int index2 = 0;
	for (int i = 1; i <= G.VexNum; i++) {
		if (G.vexs[i].data == n1) {
			index1 = i;
		}
		if (G.vexs[i].data == n2) {
			index2 = i;
		}
	}
	p2->next = G.vexs[index1].first;
	G.vexs[index1].first = p2;

	p1->next = G.vexs[index2].first;
	G.vexs[index2].first = p1;
	G.ArcNum++;

}


void print(ALGraph& G) {
	for (int i = 1; i <= G.VexNum; i++) {
		cout << G.vexs[i].data;
		ArcNode* p = G.vexs[i].first;
		while (p) {
			cout << " " << p->val;
			p = p->next;
		}
		cout << endl;
	}
}
void del_arc(ALGraph& G, int a1, int a2) {
	int i1 = 0;
	int i2 = 0;
	for (int i = 1; i <= G.VexNum; i++) {
		if (G.vexs[i].data == a1) {
			i1 = i;
		}
		if (G.vexs[i].data == a2) {
			i2 = i;
		}
	}
	ArcNode* p1 = G.vexs[i1].first;
	ArcNode* pre1 = p1;
	while (p1) {
		if (G.vexs[i1].first == p1 && p1->val == a2) {
			G.vexs[i1].first = p1->next;
			delete p1;
			break;
		}
		if (p1->val == a2) {
			pre1->next = p1->next;
			delete p1;
			break;
		}
		pre1 = p1;
		p1 = p1->next;
	}

	ArcNode* p2 = G.vexs[i2].first;
	ArcNode* pre2 = p2;

	while (p2) {
		if (G.vexs[i2].first == p2 && p2->val == a1) {
			G.vexs[i2].first = p2->next;
			delete p2;
			break;
		}
		if (p2->val == a1) {
			pre2->next = p2->next;
			delete p2;
			break;
		}
		pre2 = p2;
		p2 = p2->next;
	}
}
void Create(ALGraph& G, int n, int m) {
	G.VexNum = n;
	G.ArcNum = m;
	for (int i = 1; i <= n; i++) {
		G.vexs[i].data = i;
	}
	for (int i = 1; i <= m; i++) {
		int n1; int n2;
		cin >> n1 >> n2;
		addArc(G, n1, n2);
	}
	int a1;
	int a2;
	cin >> a1 >> a2;
	del_arc(G, a1, a2);
}

int main() {

	int n, m;
	while (cin >> n >> m && (n != 0 && m != 0)) {
		ALGraph G;
		Create(G, n, m);
		print(G);
	}

	return 0;
}