图的邻接表实现_LGraph
最后更新于：2022-04-01 20:51:53
邻接表是图的另一种有效的存储表示方法. 每个顶点u建立一个单链表, 链表中每个结点代表一条边, 为边结点. 每个单链表相当于邻接矩阵的一行.
adjVex域指示u的一个邻接点v, nxtArc指向u的下一个边结点. 如果是网, 增加一个w域存储边上的权值.
构造函数完成对一维指针数组a的动态空间存储分配, 并对其每个元素赋初值NULL. 析构函数首先释放邻接表中所有结点, 最后释放一维指针数组a所占的空间.
包含的函数Exist(): 若输入的u, v无效, 则函数返回false. 否则从a[u]指示的边结点开始, 搜索adjVex值为v的边结点, 代表边, 若搜索成功, 返回true, 否则返回false.
函数Insert(): 若输入的u, v无效, 则插入失败, 返回Failure. 否则从a[u]指示的边开始, 搜索adjVex值为v的边结点, 若不存在这样的边结点, 则创建代表边的新边结点, 并将其插在由指针a[u]所指示的单链表最前面, 并e++. 否则表示是重复边, 返回Duplicate.
函数Remove(): 若输入的u, v无效, 则删除失败, 返回Failure. 否则从a[u]指示的边开始, 搜索adjVex值为v的边结点, 若存在这样的边, 删除边, e--, 返回Success. 否则表示不存边, 返回NotPresent.
实现代码:
~~~
#include "iostream"
#include "cstdio"
#include "cstring"
#include "algorithm"
#include "queue"
#include "stack"
#include "cmath"
#include "utility"
#include "map"
#include "set"
#include "vector"
#include "list"
#include "string"
using namespace std;
typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
enum ResultCode { Underflow, Overflow, Success, Duplicate, NotPresent, Failure };
template
struct ENode
{
ENode() { nxtArc = NULL; }
ENode(int vertex, T weight, ENode *nxt) {
adjVex = vertex;
w = weight;
nxtArc = nxt;
}
int adjVex;
T w;
ENode *nxtArc;
/* data */
};
template
class Graph
{
public:
virtual ~Graph() {}
virtual ResultCode Insert(int u, int v, T &w) = 0;
virtual ResultCode Remove(int u, int v) = 0;
virtual bool Exist(int u, int v) const = 0;
/* data */
};
template
class LGraph: public Graph
{
public:
LGraph(int mSize);
~LGraph();
ResultCode Insert(int u, int v, T &w);
ResultCode Remove(int u, int v);
bool Exist(int u, int v) const;
int Vertices() const { return n; }
void Output();
protected:
ENode **a;
int n, e;
/* data */
};
template
void LGraph::Output()
{
ENode *q;
for(int i = 0; i < n; ++i) {
q = a[i];
while(q) {
cout << '(' << i << ' ' << q -> adjVex << ' ' << q -> w << ')';
q = q -> nxtArc;
}
cout << endl;
}
cout << endl << endl;
}
template
LGraph::LGraph(int mSize)
{
n = mSize;
e = 0;
a = new ENode*[n];
for(int i = 0; i < n; ++i)
a[i] = NULL;
}
template
LGraph::~LGraph()
{
ENode *p, *q;
for(int i = 0; i < n; ++i) {
p = a[i];
q = p;
while(p) {
p = p -> nxtArc;
delete q;
q = p;
}
}
delete []a;
}
template
bool LGraph::Exist(int u, int v) const
{
if(u < 0 || v < 0 || u > n - 1 || v > n - 1 || u == v) return false;
ENode *p = a[u];
while(p && p -> adjVex != v) p = p -> nxtArc;
if(!p) return false;
return true;
}
template
ResultCode LGraph::Insert(int u, int v, T &w)
{
if(u < 0 || v < 0 || u > n - 1 || v > n - 1 || u == v) return Failure;
if(Exist(u, v)) return Duplicate;
ENode *p = new ENode(v, w, a[u]);
a[u] = p;
e++;
return Success;
}
template
ResultCode LGraph::Remove(int u, int v)
{
if(u < 0 || v < 0 || u > n - 1 || v > n - 1 || u == v) return Failure;
ENode *p = a[u], *q = NULL;
while(p && p -> adjVex != v) {
q = p;
p = p -> nxtArc;
}
if(!p) return NotPresent;
if(q) q -> nxtArc = p -> nxtArc;
else a[u] = p -> nxtArc;
delete p;
e--;
return Success;
}
int main(int argc, char const *argv[])
{
LGraph lg(4);
int w = 4; lg.Insert(1, 0, w); lg.Output();
w = 5; lg.Insert(1, 2, w); lg.Output();
w = 3; lg.Insert(2, 3, w); lg.Output();
w = 1; lg.Insert(3, 0, w); lg.Output();
w = 1; lg.Insert(3, 1, w); lg.Output();
return 0;
}
~~~
';