单源点最短路径Bellman算法实现

一、数据集形式

二、数据集

三、实现代码

#include "stdafx.h"
#include "time.h"
#include <fstream>
#include<iostream>
#include <stack>
#include <queue>
#include<algorithm>
using namespace std;
int nodeNumber;
int edgeNumber;

#define PATH "E://dataset//MapSet//MinCreateTree//Testnew.txt"

//#define PATH "E://dataset//MapSet//MinCreateTree//Ol.txt"
//#define PATH "E://dataset//MapSet//MinCreateTree//TGRoad.txt"
//#define PATH "E://dataset//MapSet//MinCreateTree//California.txt"
//#define PATH "E://dataset//MapSet//MinCreateTree//San.txt"
//#define PATH "E://dataset//MapSet//MinCreateTree//NA.txt"
class CTreeNode
{
public:
CTreeNode()
{}
~CTreeNode() {}
int value;
double  weight;
CTreeNode *next;
};
class CTree
{
public:
CTree() {
weight = 65535;
}
~CTree() {}
int value;
CTreeNode *next;
CTree *before;
double weight;
};
CTree* createTree(char* filename)
{
CTree *tree;
ifstream ReadFile;
int temp;
ReadFile.open(filename, ios::in);//ios::in 表示以只读的方式读取文件
ReadFile >> nodeNumber;//第一个字符是数组长度
ReadFile >> edgeNumber;
tree = new CTree[nodeNumber];
//为树赋初值
for (int i = 0; i < nodeNumber; i++)
{
tree[i].next = NULL;
tree[i].value = i;
tree[i].before = NULL;
}
tree[0].weight = 0;
CTreeNode *nt;
while (!ReadFile.eof())            //按空格读取，遇到空白符结束
{
nt = new CTreeNode();       //读出的数据新建一个节点
ReadFile >> temp;
ReadFile >> temp;
ReadFile >> (nt->value);
ReadFile >> (nt->weight);
nt->next = tree[temp].next;
tree[temp].next = nt;
}
return tree;
}
queue<CTree *> myQ;
void Bellman(CTree *t, CTree *tree)
{
CTreeNode *p = t->next;
while (p!=NULL)
{
//链接的节点已经完成，不做任何改变
if (t->weight!=65535&&tree[p->value].weight>t->weight+p->weight)
{
//cout << tree[p->value].value << " ";
tree[p->value].weight = t->weight + p->weight;
tree[p->value].before = t;
//Bellman(tree, p->value);
myQ.push(&tree[p->value]);
}
p = p->next;
}
}
void Bell(CTree *tree)
{
myQ.push(&tree[0]);
while (!myQ.empty())
{
Bellman(myQ.front(),tree);
myQ.pop();
}
}
int main()
{
//构建图
CTree *tree = createTree(PATH);
double useTime;
clock_t start, finish;
start = clock();
//算法
Bell(tree);
finish = clock();
useTime = (double)(finish - start) / CLOCKS_PER_SEC * 1000;
printf("%f 毫秒\n", useTime);
system("pause");
return 0;
}