I would like an understanding of the following code in java without changing the meaning, it is a used to generate graphs

code

import java.io$.$BufferedWriter;

import java.io$.$FileWriter;

import java.util.$*$;

public class RandomGraph $\{$

private static final String NL $="$

$"$;

$/**$

$*$ Entrance point for the program.

$*$ java RandomGraph v$,$ e$,$ m$,$ f

$*$ @param v the first endpoint of this edge

$*$ @param e $-$ the number of edges leaving each node

$*$ @param min $-$ the lower bound on the edge capacities

$*$ @param max $-$ the upper bound on the edge capacities

$*$ @param f $-$ path and file name for saving the graph

$*/$

public static void main$($String$[]$ args$)\{$

if$($args$.$length $!=5)\{$

System.out.println$("$

Invalid parameters!"$)$;

System.out.println$("$Usage:$")$;

System.out.println$("$java RandomGraph v$,$ e$,$ min, max, f$")$;

System.out.println$("$v $-$ the number of vertices in the graph"$)$;

System.out.println$("$e $-$ the number of edges leaving each node"$)$;

System.out.println$("$min $-$ the lower bound on edge capacities"$)$;

System.out.println$("$max $-$ the upper bound on edge capacities"$)$;

System.out.println$("$f $-$ path and file name for saving this graph"$)$;

System.out.println$("$Example: java RandomGraph $9995075101$ graph$1.$txt$")$;

$\}$else if$($Integer$.$parseInt$($args$[0])>$ Integer.parseInt$($args$[1]))\{$

if$($Integer$.$parseInt$($args$[3])>=$ Integer.parseInt$($args$[2]))\{$

toFile$($graphBuilder$($Integer$.$parseInt$($args$[0]),$Integer.parseInt$($args$[1]),$Integer.parseInt$($args$[2]),$Integer.parseInt$($args$[3])),$args$[4])$;

System.out.println$("$

DONE!"$)$;

$\}$else$\{$

System.out.println$("$

FAIL!"$)$;

System.out.println$("$Max must be greater than or equal to min."$)$;

$\}$

$\}$else$\{$

System.out.println$("$

FAIL!"$)$;

System.out.println$("$The number of vertices must exceed the number of edges leaving each node."$)$;

$\}$

$\}$

$/**$

$**$ Constructor

$*$ This method creates a $3$ token representation of a graph.

$*$ @param v The number of vertices in the graph

$*$ @param e The number of edges leaving each vertice

$*$ @param min The lowerbound on the capacity value of each edge

$*$ @param max The upperbound on the capacity value of each edge

$*$ @return A string buffer, each line contains $3$ tokens corresponding

$*$ to a directed edge: the tail, the head, and the capacity.

$*/$

public static StringBuffer graphBuilder$($int v$,$ int e$,$ int min, int max$)\{$

int i;

int j;

int head;

int c;

SortedSet s;

Random gen $=$ new Random$()$;

StringBuffer bfr $=$ new StringBuffer$()$;

$//$Add distinguished node s

j $=1$;

s $=$ new TreeSet$()$;

while$($j $<=$ e$)\{$

head $=$ gen.nextInt$($v$)+1$;

if$(!$s$.$contains$($head$))\{$

s$.$add$($head$)$;

c $=$ min $+$ gen.nextInt$($max $-$ min $+1)$;

bfr$.$append$("$s$"+""+"$v$"+$head$+""+$c$+$NL$)$;

j$++$;

$\}$

$\}$

$//$Add distinguished node t

j $=1$;

s $=$ new TreeSet$()$;

while$($j $<=$ e$)\{$

int tail $=$ gen.nextInt$($v$)+1$;

if$(!$s$.$contains$($tail$))\{$

s$.$add$($tail$)$;

c $=$ min $+$ gen.nextInt$($max $-$ min $+1)$;

bfr$.$append$("$v$"+$tail$+""+"$t$"+""+$c$+$NL$)$;

j$++$;

$\}$

$\}$

$//$Add internal nodes

for$($i $=1$; i $<=$ v; i$++)\{$

s $=$ new TreeSet$()$;

s$.$add$($i$)$;

j $=1$;

while$($j $<=$ e$)\{$

head $=$ gen.nextInt$($v$)+1$;

if$(!$s$.$contains$($head$))\{$

s$.$add$($head$)$;

c $=$ min $+$ gen.nextInt$($max $-$ min $+1)$;

bfr$.$append$("$v$"+$i$+""+"$v$"+$head$+""+$c$+$NL$)$;

j$++$;

$\}$

$\}$

$\}$

return bfr;

$\}$

$/**$

$*$ This method attempts to save a string at a given location.

$*$ @param outString The StringBuffer containing the data being saved

$*$ @param filename The complete file path including file name

$*/$

private static void toFile$($StringBuffer outString, String filename$)\{$

try$\{$

BufferedWriter fout $=$ new BufferedWriter$($new FileWriter$($filename$))$;

fout.write$($outString$.$toString$())$;

fout.close$()$;

$\}$catch$($Exception e$)\{$

System.out.println$("$Error saving file."$)$;

System.out.println$("$Please check file paths and restart this program."$)$;

System.exit$(1)$;

$\}$

$\}$

$\}$

Errors

Cannot resolve symbol $\text{'}$v$\text{'}$

Cannot resolve symbol $\text{'}$e$\text{'}$

Cannot resolve symbol 'min'

Cannot resolve symbol 'max'

Cannot resolve symbol $\text{'}$f$\text{'}$

Raw use of parameterized class 'SortedSet'

Raw use of parameterized class 'TreeSet'

Unchecked call to 'add$($E$)\text{'}$ as a member of raw type 'java.util.Set'

String concatenation as argument to 'StringBuffer.append$()\text{'}$ call

Raw use of parameterized class 'TreeSet'

Unchecked call to 'add$($E$)\text{'}$ as a member of raw type 'java.util.Set'

String concatenation as argument to 'StringBuffer.append$()\text{'}$ call

Raw use of parameterized class 'TreeSet'

Unchecked call to 'add$($E$)\text{'}$ as a member of raw type 'java.util.Set'

Unchecked call to 'add$($E$)\text{'}$ as a member of raw type 'java.util.Set'

String concatenation as argument to 'StringBuffer.append$()\text{'}$ call

output expected to a faile called graph$1$

$10315$ output.txt

s v$42$

s v$65$

s v$81$

v$17$t $3$