102 lines
6.7 KiB
HTML
102 lines
6.7 KiB
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<title>ShuffleArrayList.java</title>
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<table width="100%"><tr><td align="center">/home/caleb/ASDV-Java/Semester 2/Assignments/MP5_CalebFontenot/src/main/java/com/calebfontenot/mp5_calebfontenot/ShuffleArrayList.java</td></tr></table>
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<pre>
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<span class="comment">/*</span>
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<span class="comment"> * Click </span><span class="ST0">nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt</span><span class="comment"> to change this license</span>
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<span class="comment"> * Click </span><span class="ST0">nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java</span><span class="comment"> to edit this template</span>
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<span class="comment"> */</span>
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<span class="literal">package</span> com.calebfontenot.mp5_calebfontenot;
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<span class="literal">import</span> java.util.*;
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<span class="comment">/**</span>
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<span class="comment"> *</span>
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<span class="comment"> * </span><span class="comment">@author</span> <span class="comment">caleb</span>
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<span class="comment">*/</span>
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<span class="literal">public</span> <span class="literal">class</span> ShuffleArrayList {
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<span class="literal">public</span> <span class="literal">static</span> <span class="literal">void</span> <span class="ST1">shuffle</span>(ArrayList<Number> list) {
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<span class="comment">// Create a new Random object.</span>
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Random rng = <span class="literal">new</span> Random();
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<span class="comment">// Create an ArrayList to store the indices of the elements that have been selected.</span>
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ArrayList<Integer> selectedIndices = <span class="literal">new</span> ArrayList<Integer>();
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<span class="comment">// Loop through each element in the list.</span>
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<span class="literal">for</span> (<span class="literal">int</span> i = <span class="number">0</span>; i < list.size(); ++i) {
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<span class="comment">// Generate a random index that has not been selected before.</span>
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<span class="literal">int</span> randomIndex;
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<span class="literal">do</span> {
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randomIndex = rng.nextInt(list.size()); <span class="comment">// Generate a random integer between 0 (inclusive) and the size of the list (exclusive).</span>
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} <span class="literal">while</span> (selectedIndices.contains(randomIndex)); <span class="comment">// Repeat until an unselected index is found.</span>
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selectedIndices.add(randomIndex); <span class="comment">// Add the selected index to the list of selected indices.</span>
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<span class="comment">//System.out.println(randomIndex + ", " + i);</span>
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<span class="comment">// Swap the element at the random index with the element at the current index of the loop.</span>
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<span class="comment">// This shuffles the list by randomly selecting an element to swap with the current element at each iteration.</span>
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Number temp = list.get(randomIndex); <span class="comment">// Save the element at the random index to a temporary variable.</span>
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list.set(randomIndex, list.get(i)); <span class="comment">// Overwrite the element at the random index with the element at the current index of the loop.</span>
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list.set(i, temp); <span class="comment">// Set the current index of the loop to the saved element, effectively swapping the two elements.</span>
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}
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}
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<span class="literal">public</span> <span class="literal">static</span> String <span class="ST1">checkForDuplicates</span>(ArrayList<Number> list) {
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<span class="comment">// Ensure Array does not include repeat numbers.</span>
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<span class="literal">boolean</span> repeatNumber = <span class="literal">false</span>;
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<span class="literal">for</span> (<span class="literal">int</span> i = <span class="number">0</span>; i < list.size(); ++i) {
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<span class="literal">for</span> (<span class="literal">int</span> j = <span class="number">0</span>; j < list.size(); ++j) {
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<span class="literal">if</span> (i != j) {
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<span class="comment">//System.out.println("Checking " + list.get(i) + " and " + list.get(j));</span>
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<span class="literal">if</span> (list.get(i) == list.get(j)) {
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repeatNumber = <span class="literal">true</span>;
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}
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}
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}
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}
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<span class="literal">if</span> (repeatNumber) {
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<span class="literal">return</span> <span class="string">"</span><span class="string">Numbers repeat in ArrayList.</span><span class="string">"</span>;
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} <span class="literal">else</span> {
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<span class="literal">return</span> <span class="string">"</span><span class="string">Numbers do not repeat in ArrayList.</span><span class="string">"</span>;
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}
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}
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<span class="literal">public</span> <span class="literal">static</span> <span class="literal">void</span> <span class="ST1">main</span>(String[] args) {
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<span class="literal">final</span> <span class="literal">int</span> ARRAY_SIZE = <span class="number">50</span>;
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ArrayList<Number> list = <span class="literal">new</span> ArrayList<>();
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<span class="literal">for</span> (<span class="literal">int</span> i = <span class="number">0</span>; i < ARRAY_SIZE; ++i) {
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list.add(i + <span class="number">1</span>); <span class="comment">// Fill ArrayList with sequential numbers.</span>
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}
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System.<span class="ST2">out</span>.println(list);
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System.<span class="ST2">out</span>.println(<span class="ST3">c</span><span class="ST3">heckForDuplicates</span>(list));
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<span class="ST3">shuffle</span>(list);
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System.<span class="ST2">out</span>.println(list);
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System.<span class="ST2">out</span>.println(<span class="ST3">c</span><span class="ST3">heckForDuplicates</span>(list));
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}
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}
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</pre></body>
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</html>
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