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Published byAntony Jennings Modified over 9 years ago
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Part 2
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Searching Arrays Looking for a specific element in an array E.g., whether a certain score (85) is in a list of scores Linear search Binary search
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Linear Search Does someone in the class have a score of 85? How about 90? scores If found, return its index. If not found, return -1. 86927277858978917684…
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Binary Search The scores are in ascending order. Does someone in the class have a score of 91? scores If found, return its index. If not found, return -1. 72767778848586899192…
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Sorting Arrays Selection sort Insertion sort Bubble sort Quick sort …
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Selection sort array (before the sorting): 2 6 5 3 4 1 array (after the sorting): 1 2 3 4 5 6 Selection sort: keeps finding the smallest number and places it first
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public static void selectionSort(int[] array){ for (int i = 0; i < array.length - 1; i++){ int min = array[i]; int indexOfMin = i; for (int j = i + 1; j < array.length; j++){ if (array[j] < min){ min = array[j]; indexOfMin = j; } array[indexOfMin] = array[i]; array[i] = min; }
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The Arrays Class The java.util.Arrays class contains various methods for sorting and searching arrays. int[] list = {9,3,7,5,8,2,6,1,10,4}; java.util.Arrays.sort(list);
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Exercise 1: Strictly Identical Arrays Two arrays list1 and list2 are strictly identical if they have the same length and list1[i] is equal to list2[i] for each i. Write a method that returns true if list1 and list2 are strictly identical: public static boolean equal(int[] list1, int[] list2) Write a test program that prompts the user to enter two lists of integers. Note that the first number in the input is the number of the elements in the list.
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Exercise 2: Identical Arrays Two arrays list1 and list2 are identical if they have the same contents. public static boolean equal(int[] list1, int[] list2)
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