DAA/ADA lab Programs

Merge Sort


Sort a given set of n integer elements using Merge Sort method and compute its time complexity. Run the program for varied values of n > 5000, and record the time taken to sort. Plot a graph of the time taken versus n on graph sheet. The elements can be read from a file or can be generated using the random number generator. Demonstrate using Java how the divideand - conquer method works along with its time complexity analysis: worst case, average case and best case.
import java.util.Random;
import java.util.Random;
import java.util.Scanner;
public class mergesort 
{
static int max=10000;
void merge( int[] array,int low, int mid,int high)
{
int i=low;
int j=mid+1;
int k=low;
int[]resarray;
resarray=new int[max];
while(i<=mid&&j<=high)
{
if(array[i]<array[j])
{
resarray[k]=array[i];
i++;
k++;
}
else
{
resarray[k]=array[j];
j++;
k++;
}
}
while(i<=mid)
resarray[k++]=array[i++];
while(j<=high)
resarray[k++]=array[j++];
for(int m=low;m<=high;m++)
array[m]=resarray[m];
}
void sort( int[] array,int low,int high)
{
if(low<high)
{
int mid=(low+high)/2;
sort(array,low,mid);
sort(array,mid+1,high);
merge(array,low,mid,high);
}
}
public static void main(String[] args)
{
int[] array;
int i;
System.out.println("Enter the array size");
Scanner sc =new Scanner(System.in);
int n=sc.nextInt();
array= new int[max];
Random generator=new Random();
for( i=0;i<n;i++)
array[i]=generator.nextInt(20);
System.out.println("Array before sorting");
for( i=0;i<n;i++)
System.out.println(array[i]+" ");
long startTime=System.nanoTime();
mergesort m=new mergesort();
m.sort(array,0,n-1);
long stopTime=System.nanoTime();
long elapseTime=(stopTime-startTime);
System.out.println("Time taken to sort array is:"+elapseTime+"nano seconds");
System.out.println("Sorted array is");
for(i=0;i<n;i++)
System.out.println(array[i]);
}
}
Enter the array size
10
Array before sorting
13
9
13
16
13
3
0
6
4
5
Time taken to sort array is:171277nano seconds
Sorted array is
0
3
4
5
6
9
13
13
13
16


Quick Sort

Sort a given set of n integer elements using Quick Sort method and compute its time complexity. Run the program for varied values of n > 5000 and record the time taken to sort. Plot a graph of the time taken versus n on graph sheet. The elements can be read from a file or can be generated using the random number generator. Demonstrate using Java how the divide -and- conquer method works along with its time complexity analysis: worst case, average case and best case.
import java.util.Random;

import java.util.Scanner;
public class quicksort
{
static int max=2000;
int partition (int[] a, int low,int high)
{
int p,i,j,temp;
p=a[low];
i=low+1;
j=high;
while(low<high)
{
while(a[i]<=p&&i<high)
i++;
while(a[j]>p)
j--;
if(i<j)
{
temp=a[i];
a[i]=a[j];
a[j]=temp;
}
else
{
temp=a[low];
a[low]=a[j];
a[j]=temp;
return j;
}
}
return j;
}
void sort(int[] a,int low,int high)
{
if(low<high)
{
int s=partition(a,low,high);
sort(a,low,s-1);
sort(a,s+1,high);
}
}
public static void main(String[] args)
{
// TODO Auto-generated method stub
int[] a;
int i;
System.out.println("Enter the array size");
Scanner sc =new Scanner(System.in);
int n=sc.nextInt();
a= new int[max];
Random generator=new Random();
for( i=0;i<n;i++)
a[i]=generator.nextInt(20);
System.out.println("Array before sorting");
for( i=0;i<n;i++)
System.out.println(a[i]+" ");
long startTime=System.nanoTime();
quicksort m=new quicksort();
m.sort(a,0,n-1);
long stopTime=System.nanoTime();
long elapseTime=(stopTime-startTime);
System.out.println("Time taken to sort array is:"+elapseTime+"nano seconds");
System.out.println("Sorted array is");
for(i=0;i<n;i++)
System.out.println(a[i]);
}
}
Enter the array size
10
Array before sorting
17
17
12
2
10
3
18
15
15
17
Time taken to sort array is:16980 nano seconds
Sorted array is
23
10
12
15
15
17
17
17
18


Greedy Method

Implement in Java, the 0/1 Knapsack problem using Greedy method.
import java.util.Scanner;
public class knapsacgreedy
{
public static void main(String[] args)
{
int i,j=0,max_qty,m,n;
float sum=0,max;
Scanner sc = new Scanner(System.in);
int array[][]=new int[2][20];
System.out.println("Enter no of items");
n=sc.nextInt();
System.out.println("Enter the weights of each items");
for(i=0;i=0)
{
max=0;
for(i=0;imax)
{
max=((float)array[1][i])/((float)array[0][i]);
j=i;
}
}
if(array[0][j]>m)
{
System.out.println("Quantity of item number: " + (j+1) + " added is"+m);
sum+=m*max;
m=-1;
}
else
{
System.out.println("Quantity of item
number: " + (j+1) + " added is " + array[0][j]);
m-=array[0][j];
sum+=(float)array[1][j];
array[1][j]=0;
}
}
System.out.println("The total profit is " + sum);
sc.close();
}
}
Enter no of items
3
Enter the weights of each items
20 25 10
Enter the values of each items
30 40 35
Enter maximum volume of knapsack :
40
Quantity of item number: 3 added is 10
Quantity of item number: 2 added is 25
Quantity of item number: 1 added is 5
The total profit is 82.5


Dijkstra's Algorithm

From a given vertex in a weighted connected graph, find shortest paths to other vertices using Dijkstra's algorithm. Write the program in Java.
import java.util.Scanner;
public class Dijkstra
{
int d[]=new int[10];
int p[]=new int[10];
int visited[]=new int[10];
public void dijk(int[][]a, int s, int n)
{
int u=-1,v,i,j,min;
for(v=0;v<n;v++)
{
d[v]=99;
p[v]=-1;
}
d[s]=0;
for(i=0;i<n;i++)
{
min=99;
for(j=0;j<n;j++)
{
if(d[j]<min&& visited[j]==0)
{
min=d[j];
u=j;
}
}
visited[u]=1;
for(v=0;v<n;v++)
{
if((d[u]+a[u][v]<d[v])&&(u!=v)&&visited[v]==0)
{
d[v]=d[u]+a[u][v];
p[v]=u;
}
}
}
}
void path(int v,int s)
{
if(p[v]!=-1)
path(p[v],s);
if(v!=s)
System.out.print("->"+v+" ");
}
void display(int s,int n)
{
int i;
for(i=0;i<n;i++)
{
if(i!=s)
{
System.out.print(s+" ");
path(i,s);
}
if(i!=s)
System.out.print("="+d[i]+" ");
System.out.println();
}
}
public static void main(String[] args)
{
int a[][]=new int[10][10];
int i,j,n,s;
System.out.println("enter the number of vertices");
Scanner sc = new Scanner(System.in);
n=sc.nextInt();
System.out.println("enter the weighted matrix");
for(i=0;i<n;i++)
for(j=0;j<n;j++)
a[i][j]=sc.nextInt();
System.out.println("enter the source vertex");
s=sc.nextInt();
Dijkstra tr=new Dijkstra();
tr.dijk(a,s,n);
System.out.println("the shortest path between source"+s+"to remaining
vertices are");
tr.display(s,n);
sc.close();
}
}
Output:
enter the number of vertices
5
enter the weighted matrix
0 3 99 7 99
3 0 4 2 99
99 4 0 5 6
5 2 5 0 4
99 99 6 4 0
enter the source vertex
0
the shortest path between source0to remaining vertices are
0 ->1 =3
0 ->1 ->2 =7
0 ->1 ->3 =5
0 ->1 ->3 ->4 =9


Prim's Algorithm

Find Minimum Cost Spanning Tree of a given undirected graph using Prim's algorithm. Implement the program in Java language.
import java.util.Scanner;
public class prims
{
public static void main(String[] args)
{
int w[][]=new int[10][10];
int n,i,j,s,k=0;
int min;
int sum=0;
int u=0,v=0;
int flag=0;
int sol[]=new int[10];
System.out.println("Enter the number of vertices");
Scanner sc=new Scanner(System.in);
n=sc.nextInt();
for(i=1;i<=n;i++)
sol[i]=0;
System.out.println("Enter the weighted graph");
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
w[i][j]=sc.nextInt();
System.out.println("Enter the source vertex");
s=sc.nextInt();
sol[s]=1;
k=1;
while (k<=n-1)
{
min=99;
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
if(sol[i]==1&&sol[j]==0)
if(i!=j&&min>w[i][j])
{
min=w[i][j];
u=i;
v=j;
}
sol[v]=1;
sum=sum+min;
k++;
System.out.println(u+"->"+v+"="+min);
}
for(i=1;i<=n;i++)
if(sol[i]==0)
flag=1;
if(flag==1)
System.out.println("No spanning tree");
else
System.out.println("The cost of minimum spanning tree is"+sum);
sc.close();
}
}
Output:
Enter the number of vertices
4
Enter the weighted graph
0 1 3 10
1 0 10 4
3 10 0 2
10 4 2 0
Enter the source vertex
1
1->2=1
1->3=3
3->4=2
The cost of minimum spanning tree is 6


Kruskal's Algorithm

Find Minimum Cost Spanning Tree of a given undirected graph using Kruskal's algorithm Implement the program in Java language.
import java.util.Scanner;
public class kruskal
{
int parent[]=new int[10];
int find(int m)
{
int p=m;
while(parent[p]!=0)
p=parent[p];
return p;
}
void union(int i,int j)
{
if(i<j)
parent[i]=j;
else
parent[j]=i;
}
void krkl(int[][]a, int n)
{
int u=0,v=0,min,k=0,i,j,sum=0;
while(k<n-1)
{
min=99;
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
if(a[i][j]<min&&i!=j)
{
min=a[i][j];
u=i;
v=j;
}
i=find(u);
j=find(v);
if(i!=j)
{
union(i,j);
System.out.println("("+u+","+v+")"+"="+a[u][v]);
sum=sum+a[u][v];
k++;
}
a[u][v]=a[v][u]=99;
}
System.out.println("The cost of minimum spanning tree = "+sum);
}
public static void main(String[] args)
{
int a[][]=new int[10][10];
int i,j;
System.out.println("Enter the number of vertices of the graph");
Scanner sc=new Scanner(System.in);
int n;
n=sc.nextInt();
System.out.println("Enter the wieghted matrix");
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
a[i][j]=sc.nextInt();
kruskal k=new kruskal();
k.krkl(a,n);
sc.close();
}
}
Output:
Enter the number of vertices of the graph
4
Enter the wieghted matrix
0 1 3 10
1 0 10 4
3 10 0 2
10 4 2 0
(1,2)=1
(3,4)=2
(1,3)=3
The cost of minimum spanning tree = 6


Dynamic Programming method

Implement in Java, the 0/1 Knapsack problem using Dynamic Programming method
import java.util.Scanner;
public class knapsackDP
{
public void solve(int[] wt, int[] val, int W, int N)
{
int i,j;
int[][] sol = new int[N + 1][W + 1];
for ( i = 0; i <= N; i++)
{
for ( j = 0; j <= W; j++)
{
if(i==0||j==0)
sol[i][j]=0;
else if(wt[i]>j)
sol[i][j]=sol[i-1][j];
else
sol[i][j]=Math.max((sol[i-1][j]), (sol[i - 1][j - wt[i]] + val[i]));
}
}
System.out.println("The optimal solutionis"+sol[N][W]);
int[] selected = new int[N + 1];
for(i=0;i<N+1;i++)
selected[i]=0;
i=N;
j=W;
while (i>0&&j>0)
{
if (sol[i][j] !=sol[i-1][j])
{
selected[i] = 1;
j = j - wt[i];
}
i- -;
}
System.out.println("\nItems selected : ");
for ( i = 1; i < N + 1; i++)
if (selected[i] == 1)
System.out.print(i +" ");
System.out.println();
}
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
knapsackDP ks = new knapsackDP();
System.out.println("Enter number of elements ");
int n = scan.nextInt();
int[] wt = new int[n + 1];
int[] val = new int[n + 1];
System.out.println("\nEnter weight for "+ n +" elements");
for (int i = 1; i <= n; i++)
wt[i] = scan.nextInt();
System.out.println("\nEnter value for "+ n +"
elements");
for (int i = 1; i <= n; i++)
val[i] = scan.nextInt();
System.out.println("\nEnter knapsack weight ");
int W = scan.nextInt();
ks.solve(wt, val, W, n);
}
}
Output:
Enter number of elements
3
Enter weight for 3 elements
20 25 10
Enter value for 3 elements
30 40 35
Enter knapsack weight
40
The optimal solution is 75
Items selected :
2 3


Floyd's Algorithm

Write Java programs to Implement All-Pairs Shortest Paths problem using Floyd's algorithm.

import java.util.Scanner;
public class Floyd
{
void flyd(int[][] w,int n)
{
int i,j,k;
for(k=1;k<=n;k++)
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
w[i][j]=Math.min(w[i][j], w[i][k]+w[k][j]);
}
public static void main(String[] args)
{
int a[][]=new int[10][10];
int n,i,j;
System.out.println("enter the number of vertices");
Scanner sc=new Scanner(System.in);
n=sc.nextInt();
System.out.println("Enter the weighted matrix");
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
a[i][j]=sc.nextInt();
floyd f=new floyd();
f.flyd(a, n);
System.out.println("The shortest path matrix is");
for(i=1;i<=n;i++)
{
for(j=1;j<=n;j++)
{
System.out.print(a[i][j]+" ");
}
System.out.println();
}
sc.close();
}
}
Output:
enter the number of vertices
4
Enter the weighted matrix
0 99 3 99
2 0 99 99
99 7 0 1
6 99 99 0
The shortest path matrix is
0 10 3 4
2 0 5 6
7 7 0 1
6 16 9 0


Travelling Sales Person problem

Write Java programs to Implement Travelling Sales Person problem using Dynamic programming.
import java.util.Scanner;
class TSPExp
{
int weight[][],n,tour[],finalCost;
final int INF=1000;
TSPExp()
{
Scanner s=new Scanner(System.in);
System.out.println("Enter no. of nodes:=>");
n=s.nextInt();
weight=new int[n][n];
tour=new int[n-1];
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
{
if(i!=j)
{
System.out.print("Enter weight of "+(i+1)+" to "+(j+1)+":=>");
weight[i][j]=s.nextInt();
}
}
}
System.out.println();
System.out.println("Starting node assumed to be node 1.");
eval();
}
public int COST(int currentNode,int inputSet[],int setSize)
{
if(setSize==0)
return weight[currentNode][0];
int min=INF;
int setToBePassedOnToNextCallOfCOST[]=new int[n-1];
for(int i=0;i<setSize;i++)
{
int k=0;//initialise new set
for(int j=0;j<setSize;j++)
{
if(inputSet[i]!=inputSet[j])
setToBePassedOnToNextCallOfCOST[k++]=inputSet[j];
}
int
temp=COST(inputSet[i],setToBePassedOnToNextCallOfCOST,setSize-1);
if((weight[currentNode][inputSet[i]]+temp) <min)
{
min=weight[currentNode][inputSet[i]]+temp;
}
}
return min;
}
public int MIN(int currentNode,int inputSet[],int setSize)
{
if(setSize==0)
return weight[currentNode][0];
int min=INF,minindex=0;
int setToBePassedOnToNextCallOfCOST[]=new int[n-1];
for(int i=0;i<setSize;i++) //considers each node of inputSet
{
int k=0;
for(int j=0;j<setSize;j++)
{
if(inputSet[i]!=inputSet[j])
setToBePassedOnToNextCallOfCOST[k++]=inputSet[j];
}
int
temp=COST(inputSet[i],setToBePassedOnToNextCallOfCOST,setSize-1);
if((weight[currentNode][inputSet[i]]+temp) < min)
{
min=weight[currentNode][inputSet[i]]+temp;
minindex=inputSet[i];
}
}
return minindex;
}
public void eval()
{
int dummySet[]=new int[n-1];
for(int i=1;i<n;i++)
dummySet[i-1]=i;
finalCost=COST(0,dummySet,n-1);
constructTour();
}
public void constructTour()
{
int previousSet[]=new int[n-1];
int nextSet[]=new int[n-2]; for(int i=1;i<n;i++)
previousSet[i-1]=i;
int setSize=n-1;
tour[0]=MIN(0,previousSet,setSize);
for(int i=1;i<n-1;i++)
{
int k=0;
for(int j=0;j<setSize;j++)
{
if(tour[i-1]!=previousSet[j])
nextSet[k++]=previousSet[j];
}
--setSize;
tour[i]=MIN(tour[i-1],nextSet,setSize);
for(int j=0;j<setSize;j++)
previousSet[j]=nextSet[j];
}
display();
}
public void display()
System.out.println();
System.out.print("The tour is 1-");
for(int i=0;i<n-1;i++)
System.out.print((tour[i]+1)+"-");
System.out.print("1");
System.out.println();
System.out.println("The final cost is "+finalCost);
}
}
class TSP
{
public static void main(String args[])
{
TSPExp obj=new TSPExp();
}
}
Output:
Enter no. of nodes:=>
4
Enter weight of 1 to 2:=>2
Enter weight of 1 to 3:=>5
Enter weight of 1 to 4:=>7
Enter weight of 2 to 1:=>2
Enter weight of 2 to 3:=>8
Enter weight of 2 to 4:=>3
Enter weight of 3 to 1:=>5
Enter weight of 3 to 2:=>8
Enter weight of 3 to 4:=>1
Enter weight of 4 to 1:=>7
Enter weight of 4 to 2:=>3
Enter weight of 4 to 3:=>1
Starting node assumed to be node 1.
The tour is 1-2-4-3-1
The final cost is 11




Subset

Design and implement in Java to find a subset of a given set S = {Sl, S2,.....,Sn} of n positive integers whose SUM is equal to a given positive integer d. For example, if S ={1, 2, 5, 6, 8} and d= 9, there are two solutions {1, 2, 6} and {1, 8}. Display a suitable message, if the given problem instance doesn't have a solution.

import java.util.Scanner;
import static java.lang.Math.pow;
public class subSet
{
void subset(int num,int n, int x[])
{
int i;
for(i=1;i<=n;i++)
x[i]=0;
for(i=n;num!=0;i--)
{
x[i]=num%2;
num=num/2;
}
}
public static void main(String[] args)
{
int a[]=new int[10];
int x[]=new int[10];
int n,d,sum,present=0;
int j;
System.out.println("enter the number of elements of set");
Scanner sc=new Scanner(System.in);
n=sc.nextInt();
System.out.println("enter the elements of set");
for(int i=1;i<=n;i++)
a[i]=sc.nextInt();
System.out.println("enter the positive integer sum");
d=sc.nextInt();
if(d>0)
{
for(int i=1;i<=Math.pow(2,n)-1;i++)
{
subSet s=new subSet();
s.subset(i,n,x);
sum=0;
for(j=1;j<=n;j++)
if(x[j]==1)
sum=sum+a[j];
if(d==sum)
{
System.out.print("Subset={");
present=1;
for(j=1;j<=n;j++)
if(x[j]==1)
System.out.print(a[j]+",");
System.out.print("}="+d);
System.out.println();
}
}
}
if(present==0)
System.out.println("Solution does not exists");
}
}
Output:
enter the number of elements of set
5
enter the elements of set
1 2 5 6 8
enter the positive integer sum
9
Subset={1,8,}=9
Subset={1,2,6,}=9

Hamiltonian Cycle

Design and implement in Java to find all Hamiltonian Cycles in a connected undirected Graph G of n vertices using backtracking principle.
import java.util.*;
class Hamiltoniancycle
{
private int adj[][],x[],n;
public Hamiltoniancycle()
{
Scanner src = new Scanner(System.in);
System.out.println("Enter the number of nodes");
n=src.nextInt();
x=new int[n];
x[0]=0;
for (int i=1;i<n; i++)
x[i]=-1;
adj=new int[n][n];
System.out.println("Enter the adjacency matrix");
for (int i=0;i<n; i++)
for (int j=0; j<n; j++)
adj[i][j]=src.nextInt();
}
public void nextValue (int k)
{
int i=0;
while(true)
{
x[k]=x[k]+1;
if (x[k]==n)
x[k]=-1;
if (x[k]==-1)
return;
if (adj[x[k-1]][x[k]]==1)
for (i=0; i<k; i++)
if (x[i]==x[k])
break;
if (i==k)
if (k<n-1 || k==n-1 && adj[x[n-1]][0]==1)
return;
}
}
public void getHCycle(int k)
{
while(true)
{
nextValue(k);
if (x[k]==-1)
return;
if (k==n-1)
{
System.out.println("\nSolution : ");
for (int i=0; i<n; i++)
System.out.print((x[i]+1)+" ");
System.out.println(1);
}
else getHCycle(k+1);
}
}
}
class HamiltoniancycleExp
{
public static void main(String args[])
{
Hamiltoniancycle obj=new Hamiltoniancycle();
obj.getHCycle(1);
}
}
Output:
Enter the number of nodes
6
Enter the adjacency matrix
0 1 1 1 0 0
1 0 1 0 0 1
1 1 0 1 1 0
1 0 1 0 1 0
0 0 1 1 0 1
0 1 0 0 1 0
Solution :
1 2 6 5 3 4 1
Solution :
1 2 6 5 4 3 1
Solution :
1 3 2 6 5 4 1
Solution :
1 3 4 5 6 2 1
Solution :
1 4 3 5 6 2 1
Solution :
1 4 5 6 2 3 1