Largest Number formed from an Array

formLargestNumberFromArray.java

@@ -0,0 +1,66 @@
+// Input:
+// 
+// 2
+// 5
+// 3 30 34 5 9
+// 4
+// 54 546 548 60
+
+// Output:
+//
+// 9534330
+// 6054854654
+
+
+import java.util.*;
+import java.text.*;
+import java.math.*;
+import java.util.regex.*;
+
+class formLargestNumberFromArray
+{
+    public static String A[];
+    public static void main (String[] args)
+    {
+        Scanner in = new Scanner(System.in);
+        int test = in.nextInt();
+        for(int t=0;t<test;++t){
+            int n = in.nextInt();
+            A = new String[n];
+            for(int i=0;i<n;++i)
+                A[i] = in.next();
+            Arrays.sort(A);
+            // for(int i=0;i<n;++i)
+            //     System.out.print(A[i]+" ");
+            // System.out.println();
+
+            int index = 0; 
+            int i=1;
+            for(;i<n;++i)
+                if(A[i].charAt(0)!=A[index].charAt(0)){
+                    if((i-index)>1)
+                        rearrange(index,i-1);
+                    index = i;
+                }
+            rearrange(index,i-1);
+            for(i=n-1;i>=0;--i)
+                System.out.print(A[i]);
+            System.out.println();
+        }
+    }
+    public static void rearrange(int start, int end){
+        for(int i=start+1;i<=end;++i){
+            // System.out.print("arranging "+A[i]+" >> ");
+            int j=i-1;
+            inner:for(;j>=start;--j)
+                if(((A[j]+A[i]).compareTo(A[i]+A[j]))<=0)
+                    break inner;
+            // System.out.println("before "+A[j+1]);
+            String key = A[i];
+            for(int k=i;k>j+1;--k)
+                A[k] = A[k-1];
+            A[j+1] = key; 
+        }
+    }
+}
+