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最小生成树的java代码 最小生成树的java代码是什么

一个简单的算法演示程序(JAVA语言实现)

还真敢要,别说5分了,5块钱也没人帮你做,自己想办法吧,懒鬼

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java 最小生成树

public class AbstractGraphV

{

public AbstractGraph(List?extends Edge edges, ListVvertices)

{

}

public static class Edge

{

}

}

public class WeightedGraph extends AbstractGraphFloat

{

public WeightedGraph(ListWeightedEdge edges, ListFloat vertices)

{

super(edges, vertices);

}

public static class WeightedEdge extends Edge

{

}

}

试试这种?

kruskal算法java实现,哪位大神能帮忙调通这段代码!

算法如何,就不懂了。但,代码已经正常编译、运行 了

import java.util.*;

import java.io.*;

public class KruskalTest{

private static final int m=3501981;//边数

private static final int n= 2647;  //顶点数

private static int[] parent = new int[n];//parent数组,长度为顶点数

private static ArrayListEdge list;//序列

private static float sum = 0;      //最小生成树边权总和

public static void main(String[] args)throws FileNotFoundException{

new KruskalTest().test();

}

public void test()throws FileNotFoundException{

File file=new File(".\\Euclidean distance.xlsx");

//读取文件

Scanner sc= new Scanner(file);

double number;

list = new ArrayListEdge();

for(int i=1;i=n;i++)

for(int j=i;j=n;j++)  {

Edge edge= new Edge();

edge.u=i;

edge.v=j;

if(sc.hasNext())   {

number=sc.nextDouble();

edge.w=number;

}   list.add(edge);

}

Collections.sort(list, new ComparatorEdge(){

@Override

public int compare(Edge o1, Edge o2){

return (int)(o1.w - o2.w);

}

});

//for(int i = 0;i  list.size();i++){

// Edge edge = list.get(i);

// System.out.println(edge.u + " " + edge.v + " " + edge.w) ;

// }

kruskal();

System.out.println("the length of MST is " + sum);

}

static void upset(){

for(int i = 0;i  n;i++)

parent[i] = -1;

}

int find(int x){

int s;

for(s = x;parent[s] = 0;s = parent[s]);

while(s != x){

int tmp = parent[x];

parent[x] = s;

x = tmp;

}return s;

}

void union(int R1,int R2){

int r1 = find(R1);

int r2 = find(R2);

int temp = parent[r1] + parent[r2];

if(parent[r1]  parent[r2]){

parent[r1] = r2;

parent[r2] = temp;

}else{

parent[r2] = r1;

parent[r1] = temp;

}

}

void kruskal(){

int num = 0;

int u ,v;

upset();

for(int i = 0;i  m;i++){

Edge edge = (Edge)list.get(i);

u = edge.u;

v = edge.v;

if(find(u) != find(v)){

sum += edge.w;

union(u, v);

num ++;

}

if(num = n - 1)break;

}

}

class Edge{

int u,v;

double w;

}

}

最小生成树问题

关于遗传算法解决最小生成树的问题。

这是prufer编码的代码:

#include stdio.h

#define END 0 // 结束

#define L_BRACKET 1 // 左括号

#define R_BRACKET 2 // 右括号

#define NUMBER 4 // 数

typedef struct _node

{

int value; // 节点值

int childs; // 子节点数

struct _node *parent; // 父节点

struct _node *first_child; // 第一个孩子节点

struct _node *sibling; // 下一个兄弟节点

}NODE;

typedef struct _token

{

int type; // 标记类型(左、右括号,数)

int value; // 值(仅当类型为数时有效)

}TOKEN;

typedef void (*FUNC)(NODE *);

static NODE *pSmallest = 0;// 指向最小的叶子节点

/* 取下一个标记

input 输入串

pToken 用于返回取得的标记

返回值 取走下一个标记后的输入串

*/

char *GetNextToken(char *input,TOKEN *pToken)

{

char *p,ch;

int value;

pToken-type = END;

/* 跳过空白 */

p = input;

while ((ch = *p) ch != '(' ch != ')' !isdigit(ch))

p++;

switch(ch)

{

case '(': pToken-type = L_BRACKET; p++; break;

case ')': pToken-type = R_BRACKET; p++; break;

default:

/* 识别数 */

if (isdigit(ch))

{

value = 0;

while ((ch = *p) isdigit(ch))

{

value = 10 * value + (ch - '0');

p++;

}

pToken-type = NUMBER;

pToken-value = value;

}

break;

}

/* 根据是否到达串尾返回不同的值*/

return (*p == '\0' ? 0 : p);

}

/* 根据输入内容构造树

input 输入串

返回值 构造的树的根节点指针

*/

NODE *BuildTree(char *input)

{

char *p;

TOKEN token;

NODE *pCur,*pNew,*pRoot,*pLast;

p = input; pCur = pLast = pRoot = 0;

do

{

p = GetNextToken(p,token);

switch(token.type)

{

case L_BRACKET:

break;

case R_BRACKET:

/* 回到上一级 */

pLast = pCur;

if (0 != pCur)

pCur = pCur-parent;

break;

case NUMBER:

pNew = (NODE *)malloc(sizeof(NODE));

memset(pNew,0,sizeof(NODE));

pNew-value = token.value;

/*设定父兄节点 */

pNew-parent = pCur;

if (0 != pLast)

{

pLast-sibling = pNew;

pLast = pNew;

}

if (0 != pCur)

{

if (0 == pCur-childs++)

pCur-first_child = pNew;

}

else pRoot = pNew;

p = GetNextToken(p,token);

if (token.type == L_BRACKET)

{

pCur = pNew;/*下一个符号是 (,表示此子树有孩子节点*/

pLast = 0;

}

else if (token.type == R_BRACKET)

pLast = pNew;/*下一个符号是 ),表示某子树结束了*/

break;

}

}while (0 != p);

return pRoot;

}

/* 先序遍历树,并调用指定函数对遍历到的节点进行处理

pRoot 树的根节点指针

func 用于对访问到的节点进行处理的函数

*/

void TravelTree(NODE *pRoot,FUNC func)

{

NODE *pCur;

if (0 == pRoot) return;

(*func)(pRoot);

pCur = pRoot-first_child;

while (pCur)

{

TravelTree(pCur,func);

pCur = pCur-sibling;

}

}

/* 判断指定节点是否是叶子节点(只有一条边相连的节点) */

int IsLeafNode(NODE *pNode)

{

return (0 != pNode (0 == pNode-childs 0 != pNode-parent)

|| (1 == pNode-childs 0 == pNode-parent));

}

/* 比较叶子节点值 */

void LeafValueCompare(NODE *pNode)

{

if (IsLeafNode(pNode))

if (0 == pSmallest) pSmallest = pNode;

else if (pNode-value pSmallest-value)

pSmallest = pNode;

}

/* 从树中删除指定的叶子节点

pRoot 指向树根的指针

pNode 要删除的节点指针

返回值 新的根节点指针

*/

NODE *ReleaseLeafNode(NODE *pRoot,NODE *pNode)

{

NODE *pParent,*pSibling;

if (0 == pNode-childs)

{

pParent = pNode-parent;

if (pParent)

{

pSibling = pParent-first_child;

if (pNode == pSibling)/*要删除的是父节点的第一个孩子*/

pParent-first_child = pNode-sibling;

else

{

while (pSibling pSibling-sibling != pNode)

pSibling = pSibling-sibling;

if (pSibling)

pSibling-sibling = pNode-sibling;

}

pParent-childs--;

}

free(pNode);

}

else/*根节点被删除*/

{

pRoot = pNode-first_child;

pRoot-parent = 0;

free(pNode);

}

return pRoot;

}

void ReleaseTree(NODE *pRoot)

{

NODE *pCur,*pNext;

if (pRoot)

{

pCur = pRoot-first_child;

while (pCur)

{

pNext = pCur-sibling;

ReleaseTree(pCur);

pCur = pNext;

}

free(pRoot);

}

}

int main(int argc,char *argv[])

{

NODE *pRoot;

char line[250];

int n;

while (!feof(stdin))

{

line[0] = '\0';

gets(line);

pRoot = BuildTree(line);

n = 0;

while (pRoot pRoot-childs != 0)

{

pSmallest = 0;

TravelTree(pRoot,LeafValueCompare); // 遍历树

if (0 == pSmallest-childs)

printf(n++ ? " %d" : "%d",pSmallest-parent-value);

else

printf(n++ ? " %d" : "%d",pSmallest-first_child-value);

pRoot = ReleaseLeafNode(pRoot,pSmallest);

}

if (0 != pRoot)

{

printf("\n");

ReleaseTree(pRoot);

}

}

return 0;

}

然后是遗传算法的实现:

/**************************************************************************/

/* This is a simple genetic algorithm implementation where the */

/* evaluation function takes positive values only and the */

/* fitness of an individual is the same as the value of the */

/* objective function */

/**************************************************************************/

#include stdio.h

#include stdlib.h

#include math.h

/* Change any of these parameters to match your needs */

#define POPSIZE 50 /* population size */

#define MAXGENS 1000 /* max. number of generations */

#define NVARS 3 /* no. of problem variables */

#define PXOVER 0.8 /* probability of crossover */

#define PMUTATION 0.15 /* probability of mutation */

#define TRUE 1

#define FALSE 0

int generation; /* current generation no. */

int cur_best; /* best individual */

FILE *galog; /* an output file */

struct genotype /* genotype (GT), a member of the population */

{

double gene[NVARS]; /* a string of variables */

double fitness; /* GT's fitness */

double upper[NVARS]; /* GT's variables upper bound */

double lower[NVARS]; /* GT's variables lower bound */

double rfitness; /* relative fitness */

double cfitness; /* cumulative fitness */

};

struct genotype population[POPSIZE+1]; /* population */

struct genotype newpopulation[POPSIZE+1]; /* new population; */

/* replaces the */

/* old generation */

/* Declaration of procedures used by this genetic algorithm */

void initialize(void);

double randval(double, double);

void evaluate(void);

void keep_the_best(void);

void elitist(void);

void select(void);

void crossover(void);

void Xover(int,int);

void swap(double *, double *);

void mutate(void);

void report(void);

/***************************************************************/

/* Initialization function: Initializes the values of genes */

/* within the variables bounds. It also initializes (to zero) */

/* all fitness values for each member of the population. It */

/* reads upper and lower bounds of each variable from the */

/* input file `gadata.txt'. It randomly generates values */

/* between these bounds for each gene of each genotype in the */

/* population. The format of the input file `gadata.txt' is */

/* var1_lower_bound var1_upper bound */

/* var2_lower_bound var2_upper bound ... */

/***************************************************************/

void initialize(void)

{

FILE *infile;

int i, j;

double lbound, ubound;

if ((infile = fopen("gadata.txt","r"))==NULL)

{

fprintf(galog,"\nCannot open input file!\n");

exit(1);

}

/* initialize variables within the bounds */

for (i = 0; i NVARS; i++)

{

fscanf(infile, "%lf",lbound);

fscanf(infile, "%lf",ubound);

for (j = 0; j POPSIZE; j++)

{

population[j].fitness = 0;

population[j].rfitness = 0;

population[j].cfitness = 0;

population[j].lower[i] = lbound;

population[j].upper[i]= ubound;

population[j].gene[i] = randval(population[j].lower[i],

population[j].upper[i]);

}

}

fclose(infile);

}

/***********************************************************/

/* Random value generator: Generates a value within bounds */

/***********************************************************/

double randval(double low, double high)

{

double val;

val = ((double)(rand()%1000)/1000.0)*(high - low) + low;

return(val);

}

/*************************************************************/

/* Evaluation function: This takes a user defined function. */

/* Each time this is changed, the code has to be recompiled. */

/* The current function is: x[1]^2-x[1]*x[2]+x[3] */

/*************************************************************/

void evaluate(void)

{

int mem;

int i;

double x[NVARS+1];

for (mem = 0; mem POPSIZE; mem++)

{

for (i = 0; i NVARS; i++)

x[i+1] = population[mem].gene[i];

population[mem].fitness = (x[1]*x[1]) - (x[1]*x[2]) + x[3];

}

}

/***************************************************************/

/* Keep_the_best function: This function keeps track of the */

/* best member of the population. Note that the last entry in */

/* the array Population holds a copy of the best individual */

/***************************************************************/

void keep_the_best()

{

int mem;

int i;

cur_best = 0; /* stores the index of the best individual */

for (mem = 0; mem POPSIZE; mem++)

{

if (population[mem].fitness population[POPSIZE].fitness)

{

cur_best = mem;

population[POPSIZE].fitness = population[mem].fitness;

}

}

/* once the best member in the population is found, copy the genes */

for (i = 0; i NVARS; i++)

population[POPSIZE].gene[i] = population[cur_best].gene[i];

}

/****************************************************************/

/* Elitist function: The best member of the previous generation */

/* is stored as the last in the array. If the best member of */

/* the current generation is worse then the best member of the */

/* previous generation, the latter one would replace the worst */

/* member of the current population */

/****************************************************************/

void elitist()

{

int i;

double best, worst; /* best and worst fitness values */

int best_mem, worst_mem; /* indexes of the best and worst member */

best = population[0].fitness;

worst = population[0].fitness;

for (i = 0; i POPSIZE - 1; ++i)

{

if(population[i].fitness population[i+1].fitness)

{

if (population[i].fitness = best)

{

best = population[i].fitness;

best_mem = i;

}

if (population[i+1].fitness = worst)

{

worst = population[i+1].fitness;

worst_mem = i + 1;

}

}

else

{

if (population[i].fitness = worst)

{

worst = population[i].fitness;

worst_mem = i;

}

if (population[i+1].fitness = best)

{

best = population[i+1].fitness;

best_mem = i + 1;

}

}

}

/* if best individual from the new population is better than */

/* the best individual from the previous population, then */

/* copy the best from the new population; else replace the */

/* worst individual from the current population with the */

/* best one from the previous generation */

if (best = population[POPSIZE].fitness)

{

for (i = 0; i NVARS; i++)

population[POPSIZE].gene[i] = population[best_mem].gene[i];

population[POPSIZE].fitness = population[best_mem].fitness;

}

else

{

for (i = 0; i NVARS; i++)

population[worst_mem].gene[i] = population[POPSIZE].gene[i];

population[worst_mem].fitness = population[POPSIZE].fitness;

}

}

/**************************************************************/

/* Selection function: Standard proportional selection for */

/* maximization problems incorporating elitist model - makes */

/* sure that the best member survives */

/**************************************************************/

void select(void)

{

int mem, i, j, k;

double sum = 0;

double p;

/* find total fitness of the population */

for (mem = 0; mem POPSIZE; mem++)

{

sum += population[mem].fitness;

}

/* calculate relative fitness */

for (mem = 0; mem POPSIZE; mem++)

{

population[mem].rfitness = population[mem].fitness/sum;

}

population[0].cfitness = population[0].rfitness;

/* calculate cumulative fitness */

for (mem = 1; mem POPSIZE; mem++)

{

population[mem].cfitness = population[mem-1].cfitness +

population[mem].rfitness;

}

/* finally select survivors using cumulative fitness. */

for (i = 0; i POPSIZE; i++)

{

p = rand()%1000/1000.0;

if (p population[0].cfitness)

newpopulation[i] = population[0];

else

{

for (j = 0; j POPSIZE;j++)

if (p = population[j].cfitness

ppopulation[j+1].cfitness)

newpopulation[i] = population[j+1];

}

}

/* once a new population is created, copy it back */

for (i = 0; i POPSIZE; i++)

population[i] = newpopulation[i];

}

/***************************************************************/

/* Crossover selection: selects two parents that take part in */

/* the crossover. Implements a single point crossover */

/***************************************************************/

void crossover(void)

{

int i, mem, one;

int first = 0; /* count of the number of members chosen */

double x;

for (mem = 0; mem POPSIZE; ++mem)

{

x = rand()%1000/1000.0;

if (x PXOVER)

{

++first;

if (first % 2 == 0)

Xover(one, mem);

else

one = mem;

}

}

}

/**************************************************************/

/* Crossover: performs crossover of the two selected parents. */

/**************************************************************/

void Xover(int one, int two)

{

int i;

int point; /* crossover point */

/* select crossover point */

if(NVARS 1)

{

if(NVARS == 2)

point = 1;

else

point = (rand() % (NVARS - 1)) + 1;

for (i = 0; i point; i++)

swap(population[one].gene[i], population[two].gene[i]);

}

}

/*************************************************************/

/* Swap: A swap procedure that helps in swapping 2 variables */

/*************************************************************/

void swap(double *x, double *y)

{

double temp;

temp = *x;

*x = *y;

*y = temp;

}

/**************************************************************/

/* Mutation: Random uniform mutation. A variable selected for */

/* mutation is replaced by a random value between lower and */

/* upper bounds of this variable */

/**************************************************************/

void mutate(void)

{

int i, j;

double lbound, hbound;

double x;

for (i = 0; i POPSIZE; i++)

for (j = 0; j NVARS; j++)

{

x = rand()%1000/1000.0;

if (x PMUTATION)

{

/* find the bounds on the variable to be mutated */

lbound = population[i].lower[j];

hbound = population[i].upper[j];

population[i].gene[j] = randval(lbound, hbound);

}

}

}

/***************************************************************/

/* Report function: Reports progress of the simulation. Data */

/* dumped into the output file are separated by commas */

/***************************************************************/

void report(void)

{

int i;

double best_val; /* best population fitness */

double avg; /* avg population fitness */

double stddev; /* std. deviation of population fitness */

double sum_square; /* sum of square for std. calc */

double square_sum; /* square of sum for std. calc */

double sum; /* total population fitness */

sum = 0.0;

sum_square = 0.0;

for (i = 0; i POPSIZE; i++)

{

sum += population[i].fitness;

sum_square += population[i].fitness * population[i].fitness;

}

avg = sum/(double)POPSIZE;

square_sum = avg * avg * POPSIZE;

stddev = sqrt((sum_square - square_sum)/(POPSIZE - 1));

best_val = population[POPSIZE].fitness;

fprintf(galog, "\n%5d, %6.3f, %6.3f, %6.3f \n\n", generation,

best_val, avg, stddev);

}

/**************************************************************/

/* Main function: Each generation involves selecting the best */

/* members, performing crossover mutation and then */

/* evaluating the resulting population, until the terminating */

/* condition is satisfied */

/**************************************************************/

void main(void)

{

int i;

if ((galog = fopen("galog.txt","w"))==NULL)

{

exit(1);

}

generation = 0;

fprintf(galog, "\n generation best average standard \n");

fprintf(galog, " number value fitness deviation \n");

initialize();

evaluate();

keep_the_best();

while(generationMAXGENS)

{

generation++;

select();

crossover();

mutate();

report();

evaluate();

elitist();

}

fprintf(galog,"\n\n Simulation completed\n");

fprintf(galog,"\n Best member: \n");

for (i = 0; i NVARS; i++)

{

fprintf (galog,"\n var(%d) = %3.3f",i,population[POPSIZE].gene[i]);

}

fprintf(galog,"\n\n Best fitness = %3.3f",population[POPSIZE].fitness);

fclose(galog);

printf("Success\n");

}

/***************************************************************/

如何用此遗传算法解决最小生成树的问题呢,要求先随机初始化一个图,然后生成对应的最小生成树。

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用java写了一个最小生成树问题的程序,在进行快速排序边长的权重时,出现了下面的报错

说明 edges[] edgelist1= g.listedges(graph1); 中的 listedges 方法有问题

class graph {

public double[][] generate(int n) {

return null;

}

public double[] listlength(double[][] d) {

return null;

}

public edges[] listedges(double [][] d) {

return null;

}

}

全返回null的,,,,,,,,,都还没做

题目1:一个简单的算法演示程序(JAVA语言实现)

1. 选择一个算法(提供选择见下),利用各种方法(图形、动画等)演示算法的演示过程。

2. 可以进行手动演示,也可以自动步进式演示。

3. 允许用户设置算法的各个输入参数,以及自动步进式演示中的时间间隔。

4. 不同的算法输入要求见下。

界面要求:

1. 尽量使用图形界面实现,要符合日常软件使用规范来设计菜单和界面。

2. 如果无法实现图形界面,则在命令行方式下也需要提供菜单,方便用户操作。

其他要求:

1. 标识符命名遵循Windows命名规范。

2. 能够注意各种异常处理,注重提高程序运行效率。

提交内容:

1. 全部源代码。

2. 软件设计和使用说明书(UML类图;实现的功能、主要技术;使用帮助文档)

参考算法:

1. 最小生成树算法:Prim算法、Kruskal算法。允许以下方式输入一个图形:绘制图形、输入邻接矩阵、输入边及其关联的顶点。要求在图形方式下进行演示算法执行步骤。

2. 单源最短路算法:Dijkstra算法。允许以下方式输入一个图形:绘制图形、输入邻接矩阵、输入边及其关联的顶点。要求在图形方式下进行演示算法执行步骤。

3. 最优编码算法:Huffman编码算法。允许用户输入一段英文文字,或者打开一个txt文档(英文内容),据此文档内容进行编码。要求动态列出每个字符的出现概率统计结果以及对应编码。

4. 其他可供演示的具有一定难度的算法,如关键路径问题、有向图的极大连通分支等。


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