Java InterpolationSearch
Java InterpolationSearch
/** * <html> * <body> * <P> Copyright 1994-2018 JasonInternational </p> * <p> All rights reserved.</p> * <p> Created on 2018年4月10日 上午9:46:32</p> * <p> Created by Jason</p> * </body> * </html> */ package cn.ucaner.algorithm.search; /** * Interpolation search is an algorithm for searching for a given key in an indexed array that has been ordered by numerical values assigned to the keys (key values). It parallels how humans search * through a telephone book for a particular name, the key value by which the book's entries are ordered. * <p> * Worst-case performance O(n)<br> * Average performance O(log(log(n)))<br> * <p> * @see <a href="https://en.wikipedia.org/wiki/Interpolation_search">Interpolation Search (Wikipedia)</a> * <br> * @author Justin Wetherell <phishman3579@gmail.com> */ public class InterpolationSearch { private static int[] sorted = null; // Assuming the array is sorted public static final int find(int value, int[] array) { InterpolationSearch.sorted = array; try { return recursiveFind(value, 0, InterpolationSearch.sorted.length - 1); } finally { InterpolationSearch.sorted = null; } } private static int recursiveFind(int value, int start, int end) { if (start == end) { int lastValue = sorted[start]; // start==end if (value == lastValue) return start; // start==end return Integer.MAX_VALUE; } final int mid = start + ((value - sorted[start]) * (end - start)) / (sorted[end] - sorted[start]); if (mid < 0 || mid > end) return Integer.MAX_VALUE; int midValue = sorted[mid]; if (value == midValue) return mid; if (value > midValue) return recursiveFind(value, mid + 1, end); return recursiveFind(value, start, mid - 1); } }
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勿忘初心 方得始终
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