68 lines
1.8 KiB
Java
68 lines
1.8 KiB
Java
/**
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* Array utils for ints
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* @author Isaac Shoebottom (3429069)
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*/
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public class IntArrayUtil {
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/**
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* Appends an array to another array
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* @param arrA First array in append
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* @param arrB Second array in append
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* @return Appended array
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*/
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public static int[] append (int[] arrA, int[] arrB) {
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int appendedLength = arrA.length + arrB.length;
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int[] appended = new int[appendedLength];
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for(int i = 0; i < arrA.length; i++) {
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appended[i] = arrA[i];
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}
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for(int i = 0; i < arrB.length; i++) {
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appended[i + arrA.length] = arrB[i];
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}
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return appended;
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}
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/**
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* Reverse the order of elements in a string
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* @param arr The array to be reversed
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* @return The reversed array
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*/
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public static int[] reverse (int[] arr) {
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int[] reversed = new int[arr.length];
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for(int i =0; i<arr.length; i++ ) {
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reversed[i] = arr[i];
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}
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for(int i = 0; i < arr.length/2; i++) {
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int temp = reversed[i];
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reversed[i] = arr[(arr.length-1) - i];
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reversed[(arr.length-1) - i] = temp;
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}
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return reversed;
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}
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/**
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* Subtracts every odd index from a string from every even index
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* @param arr The array to perform math on
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* @return The alternating sum of the array
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*/
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public static int alternatingSum (int[] arr) {
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int positives = 0;
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int negatives = 0;
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boolean isPos = true;
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for (int j : arr)
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if (isPos) {
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positives += j;
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isPos = false;
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} else {
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negatives += j;
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isPos = true;
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}
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return positives-negatives;
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}
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}
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