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copied!<p>You can use an <code>ArrayList</code> to store the indexes:</p> <pre><code>List<Integer> indexes = new ArrayList<Integer>(); for (int i = 0; i < 1000; i++){ if (sWorld[i].length > 4) { //add i to a list (not an array yet) indexes.add(i); } ... } // then sort the list // not necessary, as indexes are inserted in the right order, but if you must... // Collections.sort(indexes); // and, if you need an array instead of a list Integer[] indexesArray = indexes.toArray(new Integer[indexes.size()]); </code></pre> <p>A <code>List</code>, or an <code>ArrayList</code>, work as variable-length arrays. Though not as efficiently as an actual array.</p> <p>As seen above, there is no need to sort the array later, but, if you must, you can use <code>Collections.sort()</code>.</p> <p>Also, if you must have an <code>int[]</code> instead of an <code>Integer[]</code>, please check: <a href="https://stackoverflow.com/questions/960431/how-to-convert-listinteger-to-int-in-java">How to convert List<Integer> to int[] in Java?</a></p> <p><strong>Update:</strong></p> <p>As you want to know the size and index of the bigger arrays, it's a whole new problem. Below is a working code that deals with it.</p> <p>Basically, everytime you find an array with size larger than 4, you add a pair <code>(index, size)</code> to the list. This list is then ordered by size, in descending order.</p> <p><strong>At the end of the <code>main()</code> method, an array is created (<code>int[] topTenIndexes</code>) which contains the indexes of the 10 biggest arrays (the indexes are presented in descending order of it's array's length). The result is -1 when there weren't enough big (length > 4) arrays.</strong></p> <pre><code>import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; public class Example { public static void main(String[] args) { List<ArrayIndexAndSize> indexes = new ArrayList<ArrayIndexAndSize>(); int[][] sWorld = {{1},{2,5,5,5,5},{3,6,6,6,6,6}}; for (int i = 0; i < sWorld.length; i++){ if (sWorld[i].length > 4) { // add a pair (index, size) to the list indexes.add(new ArrayIndexAndSize(i, sWorld[i].length)); } //... } // then sort the list by array SIZE, in descending order Collections.sort(indexes); // Print it! System.out.println(indexes); /* output: "[[Array index: 2; Array size: 6], [Array index: 1; Array size: 5]]" */ // Generating an array with the top ten indexes int[] topTenIndexes = new int[10]; Arrays.fill(topTenIndexes, -1); for (int i = 0; i < indexes.size() && i < 10; i++) { topTenIndexes[i] = indexes.get(i).index; } // Print it System.out.println(Arrays.toString(topTenIndexes)); /* output: [2, 1, -1, -1, -1, -1, -1, -1, -1, -1] */ } public static class ArrayIndexAndSize implements Comparable<ArrayIndexAndSize> { public int index; public int size; public ArrayIndexAndSize(int index, int size) { this.index = index; this.size = size; } /* Order by size, DESC */ /* This is called by Collections.sort and defines the order of two elements */ public int compareTo(ArrayIndexAndSize another) { int thisVal = this.size; int anotherVal = another.size; return -(thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1)); } @Override public String toString() { return "[Array index: "+index+"; Array size: "+size+"]"; } } } </code></pre>

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