Create matrix_mult.java

Author: jaypatel1398

DP/MatrixChain_multiplication/matrix_mult.java

@@ -0,0 +1,92 @@
+//package matchain1;
+import java.io.*;
+import java.util.*;
+public class matchain1
+{
+    public static int[] brr = new int[100];
+    public static int g = 0;
+    public static int[][] breakmatrix = new int[100][100];
+    public static int[][] matrix(int[] arr,int n)
+    {
+        int[][] mat = new int[n+1][n+1];
+        for(int i=0;i<=n;i++)
+        {
+            Arrays.fill(mat[i],0);
+            Arrays.fill(breakmatrix[i],0);
+        }
+        for(int i=1;i<n;i++)
+        {
+            for(int j=1;j<n-i+1;j++)
+            {
+                int l = j+i;
+                mat[j][l] = Integer.MAX_VALUE;
+                for(int k=j;k<l;k++)
+                {
+                    int temp = mat[j][k] + mat[k+1][l] + arr[j-1]*arr[k]*arr[l];
+                    if(temp<mat[j][l])
+                    {
+                        mat[j][l] = temp;
+                        breakmatrix[j][l] = k;
+                    }
+                }
+            }
+        }
+        int temp = 0;
+        for(int i=0;i<=n;i++){
+            for(int j=0;j<=n;j++){
+                System.out.print(breakmatrix[i][j] + " ");
+            }
+            System.out.println();
+        }
+        for(int i=0;i<=n;i++){
+            for(int j=0;j<=n;j++){
+                System.out.print(mat[i][j] + " ");
+            }
+            System.out.println();
+        }
+        System.out.println("The optimal solution is : " + mat[1][n]);
+        return breakmatrix;
+    }
+    public static void print(int i,int j)
+    {
+        if(Math.abs(j-i)<2)
+            return;
+        brr[g] = breakmatrix[i][j];
+        g++;
+        print(i,breakmatrix[i][j]);
+        print(breakmatrix[i][j]+1,j);
+        
+    }
+    public static void printmatrix(int[] a)
+    {
+        ArrayList<String> s = new ArrayList<String>();
+        for(int i=0;i<a.length-1;i++)
+        {
+            String t = "(" + a[i] + "X" +a[i+1] + ")";
+            s.add(t);
+        }
+        for(int j=0;j<g;j++)
+        {
+            s.add(brr[j],"|");
+        }
+        for(int i=0;i<s.size();i++)
+        {
+            System.out.print(s.get(i) + " ");
+        }
+    }
+    public static void main(String[] args)
+    {
+        Scanner scan  = new Scanner(System.in);
+        int n = scan.nextInt();
+        int[] a = new int[n+1];
+        for(int i=0;i<=n;i++)
+        {
+            a[i] = scan.nextInt();
+        }
+        int[][] kmat = matrix(a,n);
+        print(1,n);
+        System.out.println("The optimal way for multiplication is: ");
+        printmatrix(a);
+    }
+    
+}