CompactArray.java

public class CompactArray {
 public static void main(String[] args) {
  CompactArray c = new CompactArray();
  int[] sampleArray = {-1,5,3,-1,3,5,2,1,-1,6};
  System.out.print(" Input : ");printArray(sampleArray, sampleArray.length);
  int validIndex = c.compact(sampleArray);
  System.out.print("Output : ");printArray(sampleArray, validIndex);
 }
 
 private int compact(int[] arr){
  int k = 0;
  for(int i=0;i<arr.length;i++){
   if(arr[i]!=-1)
    arr[k++] = arr[i];
  }
  return k;
 }
 
 private static void printArray(int[] sampleArray, int validIndex) {
  for(int i=0;i<validIndex;i++){
   System.out.print(sampleArray[i]+" ");
  }
  System.out.println();
 }
}
/*
Input : -1 5 3 -1 3 5 2 1 -1 6 
Output : 5 3 3 5 2 1 6 
*/