C++示例详解Prim算法与优先队列

#include <stdio.h>
#include <malloc.h>
#define VERTEXNUM 6
void createGraph(int (*edge)[VERTEXNUM], int start, int end, int value);
void displayGraph(int (*edge)[VERTEXNUM]);
void prim(int (*edge)[VERTEXNUM], int (**tree)[VERTEXNUM], int startVertex, int* vertexStatusArr);
int main(void){
	//动态创建存放边的二维数组  
        int (*edge)[VERTEXNUM] = (int (*)[VERTEXNUM])malloc(sizeof(int)*VERTEXNUM*VERTEXNUM);
        int i,j;
        for(i=0;i<VERTEXNUM;i++){
                for(j=0;j<VERTEXNUM;j++){
                        edge[i][j] = 0;
                }
        }
	//存放顶点的遍历状态，0：未遍历，1：已遍历 
        int* vertexStatusArr = (int*)malloc(sizeof(int)*VERTEXNUM);
        for(i=0;i<VERTEXNUM;i++){
                vertexStatusArr[i] = 0;
        }
        printf("after init:\n");
        displayGraph(edge);
	//创建图  
        createGraph(edge,0,1,6);
        createGraph(edge,0,3,5);
        createGraph(edge,0,2,1);
        createGraph(edge,1,2,5);
        createGraph(edge,1,4,3);
        createGraph(edge,2,4,6);
        createGraph(edge,2,3,5);
        createGraph(edge,2,5,4);
        createGraph(edge,3,5,2);
        createGraph(edge,4,5,6);
        printf("after create:\n");
        displayGraph(edge);
	//最小生成树
        int (*tree)[VERTEXNUM] = NULL;
        prim(edge, &tree, 0, vertexStatusArr);
        printf("after generate tree:\n");
        displayGraph(tree);
        free(edge);
        free(tree);
        return 0;
}
//创建图
void createGraph(int (*edge)[VERTEXNUM], int start, int end, int value){
        edge[start][end] = value;
        edge[end][start] = value;
}
//打印存储的图
void displayGraph(int (*edge)[VERTEXNUM]){
        int i,j;
        for(i=0;i<VERTEXNUM;i++){
                for(j=0;j<VERTEXNUM;j++){
                        printf("%d ",edge[i][j]);
                }
                printf("\n");
        }
}
void prim(int (*edge)[VERTEXNUM], int (**tree)[VERTEXNUM], int startVertex, int* vertexStatusArr){
	//申请存储树的内存
        *tree = (int (*)[VERTEXNUM])malloc(sizeof(int)*VERTEXNUM*VERTEXNUM);
        int i,j;
        for(i=0;i<VERTEXNUM;i++){
                for(j=0;j<VERTEXNUM;j++){
                       (*tree)[i][j] = 0;
                }
        }
	//从顶点0开始，则顶点0就是已访问的
        vertexStatusArr[0] = 1;
        int least, start, end, vNum = 1;
	//如果还顶点还没有访问完
        while(vNum < VERTEXNUM){
                least = 9999;
                for(i=0;i<VERTEXNUM;i++){
			//选择已经访问过的点
                        if(vertexStatusArr[i] == 1){
                                for(j=0;j<VERTEXNUM;j++){
					//选择一个没有访问过的点
                                        if(vertexStatusArr[j] == 0){
						//选出一条value最小的边
                                                if(edge[i][j] != 0 && edge[i][j] < least){
                                                        least = edge[i][j];
                                                        start = i;
                                                        end = j;
                                                }
                                        }
                                }
                        }
                }
                vNum++;
		//将点设置为访问过
                vertexStatusArr[end] = 1;
		//将边加到树中
                createGraph(*tree,start,end,least);
        }
}

#include <iostream>
#include <queue>
using namespace std;
//方法1
struct tmp1 //运算符重载<
{
    int x;
    tmp1(int a) {x = a;}
    bool operator<(const tmp1& a) const
    {
        return x < a.x; //大顶堆
    }
};
//方法2
struct tmp2 //重写仿函数
{
    bool operator() (tmp1 a, tmp1 b)
    {
        return a.x < b.x; //大顶堆
    }
};
int main()
{
    tmp1 a(1);
    tmp1 b(2);
    tmp1 c(3);
    priority_queue<tmp1> d;
    d.push(b);
    d.push(c);
    d.push(a);
    while (!d.empty())
    {
        cout << d.top().x << '\n';
        d.pop();
    }
    cout << endl;
    priority_queue<tmp1, vector<tmp1>, tmp2> f;
    f.push(b);
    f.push(c);
    f.push(a);
    while (!f.empty())
    {
        cout << f.top().x << '\n';
        f.pop();
    }
}

#include <iostream>
#include <queue>
using namespace std;
//方法1
struct tmp1 //运算符重载<
{
    int x;
    tmp1(int a) {x = a;}
    bool operator<(const tmp1& a) const
    {
        return x < a.x; //大顶堆
    }
};
//方法2
struct tmp2 //重写仿函数
{
    bool operator() (tmp1 a, tmp1 b)
    {
        return a.x < b.x; //大顶堆
    }
};
int main()
{
    tmp1 a(1);
    tmp1 b(2);
    tmp1 c(3);
    priority_queue<tmp1> d;
    d.push(b);
    d.push(c);
    d.push(a);
    while (!d.empty())
    {
        cout << d.top().x << '\n';
        d.pop();
    }
    cout << endl;
    priority_queue<tmp1, vector<tmp1>, tmp2> f;
    f.push(b);
    f.push(c);
    f.push(a);
    while (!f.empty())
    {
        cout << f.top().x << '\n';
        f.pop();
    }
}