2019-09-28 16:26:10 +08:00
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package Maths;
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public class FindMaxRecursion {
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public static void main(String[] args) {
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int[] array = {2, 4, 9, 7, 19, 94, 5};
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int low = 0;
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int high = array.length - 1;
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2020-08-10 16:52:06 +08:00
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assert max(array, low, high) == 94;
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assert max(array, array.length) == 94;
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2019-09-28 16:26:10 +08:00
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}
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/**
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* Get max of array using divide and conquer algorithm
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*
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* @param array contains elements
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* @param low the index of the first element
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* @param high the index of the last element
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* @return max of {@code array}
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*/
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public static int max(int[] array, int low, int high) {
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if (low == high) {
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return array[low]; //or array[high]
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}
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int mid = (low + high) >>> 1;
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int leftMax = max(array, low, mid); //get max in [low, mid]
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int rightMax = max(array, mid + 1, high); //get max in [mid+1, high]
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2020-08-10 16:52:06 +08:00
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return Math.max(leftMax, rightMax);
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}
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/**
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* Get max of array using recursion algorithm
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*
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* @param array contains elements
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* @param len length of given array
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* @return max value of {@code array}
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*/
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public static int max(int[] array, int len) {
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return len == 1 ? array[0] : Math.max(max(array, len - 1), array[len - 1]);
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2019-09-28 16:26:10 +08:00
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}
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}
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