怎么调用该函数:void Prim(MatGraph g,int v) { int lowcost[MAXV]; int min; int closest[MAXV],i,j,k; for (i=0;i<g.n;i++) //给lowcost[]和closest[]置初值 { lowcost[i]=g.edges[v][i]; closest[i]=v; } for (i=1;i<g.n;i++) //输出(n-1)条边 { min=INF; for (j=0;j<g.n;j++) //在(V-U)中找出离U最近的顶点k if (lowcost[j]!=0 && lowcost[j]<min) { min=lowcost[j]; k=j; //k记录最近顶点编号 } printf(" 边(%d,%d)权为:%d\n",closest[k],k,min); lowcost[k]=0; //标记k已经加入U for (j=0;j<g.n;j++) //修改数组lowcost和closest if (lowcost[j]!=0 && g.edges[k][j]<lowcost[j]) { lowcost[j]=g.edges[k][j]; closest[j]=k; } } }
时间: 2024-01-02 10:03:24 浏览: 25
这是一个使用 Prim 算法求解最小生成树的函数,调用时需要传入一个 MatGraph 类型的图和一个起始顶点的编号 v。可以按如下方式调用:
```c++
MatGraph g; // 假设已经创建了一个 MatGraph 类型的图
int v = 0; // 假设起始顶点为 0
Prim(g, v); // 调用 Prim 算法求解最小生成树
```
相关问题
#define _CRT_SECURE_NO_WARNINGS 1 #include <stdio.h> #include <malloc.h> #define MAXV 6 typedef struct{ int no; char info; }VertexType; typedef struct { int edges[MAXV][MAXV]; int n, e; VertexType vexs[MAXV]; }MatGraph; void CreateMat(MatGraph *g, int A[MAXV][MAXV], int n, int e) { int i, j; MatGraph g.n = n; g.e = e; for (i = 0; i < g.n; i++) for (j = 0; j < g.n; j++) g.edges[i][j] = A[i][j]; } void DispMat(MatGraph g) { int i, j; for (i = 0; i < j.n; i++) { for (j = 0; j < g.n; j++) if (g.edges[i][j] != INF) printf("%4d", g.edges[i][j]); else printf("%4s", ""); } } int Prim(MatGraph g, int v) { int lowcost[MAXV], min, n = g.n, sum; int closest[MAXV], i, j,k; for (i = 1; i < n; i++) { min = INF; for(j=0;j<n;j++)\ if (lowcost[j] != 0 && g.edges[k][j] < lowcost[j]) { min = lowcost[j]; k = j; } printf("距离为: ", closest[k] + 1, k + 1, min * 10); sum = sum + min; lowcost[k] = 0; for(j=0;j<n;j++) if (g.edges[k][j] != 0 && g.edges[k][j] < lowcost[j]) { lowcost[j] = g.edges[k][j]; closest[j] = k; } } int main() { int v = 3, k; MatGraph g; int A[MAXV][MAXV] = { {0,6,1,5,INF,INF} , {6,0,5,INF,3,INF} , {1 ,5,0,5,6,4} , {5,INF,5,0,INF,2}, {INF,3,6,INF,0,6}, { INF,INF,4,2,6,0} }; int n = 6, e = 10; CreateMat(g, A, n, e); printf("城市连接图的邻接矩阵:\n"); DispMat(g); printf("\n求解结果:/n"); k = Prim(g, 0); printf("总最短距离为:\n", k * 10); return 1; }正确代码
以下是修改后的正确代码,已经修复了原来代码中的错误:
```
#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <malloc.h>
#define MAXV 6
#define INF 9999
typedef struct {
int no;
char info;
} VertexType;
typedef struct {
int edges[MAXV][MAXV];
int n, e;
VertexType vexs[MAXV];
} MatGraph;
void CreateMat(MatGraph* g, int A[MAXV][MAXV], int n, int e) {
int i, j;
g->n = n;
g->e = e;
for (i = 0; i < g->n; i++)
for (j = 0; j < g->n; j++)
g->edges[i][j] = A[i][j];
}
void DispMat(MatGraph g) {
int i, j;
for (i = 0; i < g.n; i++) {
for (j = 0; j < g.n; j++)
if (g.edges[i][j] != INF)
printf("%4d", g.edges[i][j]);
else
printf("%4s", "");
printf("\n");
}
}
int Prim(MatGraph g, int v) {
int lowcost[MAXV], min, n = g.n, sum = 0;
int closest[MAXV], i, j, k;
for (i = 0; i < n; i++) {
lowcost[i] = g.edges[v][i];
closest[i] = v;
}
lowcost[v] = 0;
for (i = 1; i < n; i++) {
min = INF;
for (j = 0; j < n; j++)
if (lowcost[j] != 0 && lowcost[j] < min) {
min = lowcost[j];
k = j;
}
printf("%d-%d距离为:%d\n", closest[k] + 1, k + 1, min);
sum += min;
lowcost[k] = 0;
for (j = 0; j < n; j++)
if (g.edges[k][j] != 0 && g.edges[k][j] < lowcost[j]) {
lowcost[j] = g.edges[k][j];
closest[j] = k;
}
}
return sum;
}
int main()
{
int k;
MatGraph g;
int A[MAXV][MAXV] = {
{0, 6, 1, 5, INF, INF},
{6, 0, 5, INF, 3, INF},
{1, 5, 0, 5, 6, 4},
{5, INF, 5, 0, INF, 2},
{INF, 3, 6, INF, 0, 6},
{INF, INF, 4, 2, 6, 0}
};
int n = 6, e = 10;
CreateMat(&g, A, n, e);
printf("城市连接图的邻接矩阵:\n");
DispMat(g);
printf("求解结果:\n");
k = Prim(g, 0);
printf("总最短距离为:%d\n", k);
return 0;
}
```
#include <stdio.h> #include <malloc.h> #define MAXV 6 #define INF 9999 typedef struct { int no; char info; } VertexType; typedef struct { int edges[MAXV][MAXV]; int n, e; VertexType vexs[MAXV]; } MatGraph; void CreateMat(MatGraph* g, int A[MAXV][MAXV], int n, int e) { int i, j; g->n = n; g->e = e; for (i = 0; i < g->n; i++) for (j = 0; j < g->n; j++) g->edges[i][j] = A[i][j]; } void DispMat(MatGraph g) { int i, j; for (i = 0; i < g.n; i++) { for (j = 0; j < g.n; j++) if (g.edges[i][j] != INF) printf("%4d", g.edges[i][j]); else printf("%4s", ""); printf("\n"); } } int Prim(MatGraph g, int v) { int lowcost[MAXV], min, n = g.n, sum = 0; int closest[MAXV], i, j, k; for (i = 0; i < n; i++) { lowcost[i] = g.edges[v][i]; closest[i] = v; } lowcost[v] = 0; for (i = 1; i < n; i++) { min = INF; for (j = 0; j < n; j++) if (lowcost[j] != 0 && lowcost[j] < min) { min = lowcost[j]; k = j; } printf("%d-%d距离为:%d\n", closest[k] + 1, k + 1, min); sum += min; lowcost[k] = 0; for (j = 0; j < n; j++) if (g.edges[k][j] != 0 && g.edges[k][j] < lowcost[j]) { lowcost[j] = g.edges[k][j]; closest[j] = k; } } return sum; } int main() { int k; MatGraph g; int A[MAXV][MAXV] = { {0, 6, 1, 5, INF, INF}, {6, 0, 5, INF, 3, INF}, {1, 5, 0, 5, 6, 4}, {5, INF, 5, 0, INF, 2}, {INF, 3, 6, INF, 0, 6}, {INF, INF, 4, 2, 6, 0} }; int n = 6, e = 10; CreateMat(&g, A, n, e); printf("城市连接图的邻接矩阵:\n"); DispMat(g); printf("求解结果:\n"); k = Prim(g, 0); printf("总最短距离为:%d\n", k); return 0; }改错
代码中存在以下问题:
1. 使用了未定义的宏INF。应该在头文件中定义INF,例如: #define INF 9999。
2. 在 CreateMat 函数中,应该使用参数e来初始化 g->e,而不是使用常量值10。应该修改为: g->e = e;
3. 在 DispMat 函数中,当 g.edges[i][j]为INF时,应该输出一个空格,而不是四个空格。应该修改为: printf(" ");
4. 在 Prim 函数中,应该将距离最短的点的下标k加1后输出,而不是直接输出k。应该修改为: printf("%d-%d距离为:%d\n", closest[k] + 1, k + 1, min);
修改后的代码如下:
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