Java 使用二进制搜索查找数组中的项。
使用二进制搜索查找数组中的项。
实例源码：
源代码：
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/*2
from 时 代 J a v a 公 众 号 - nowjava.com 3
*/4
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import java.security.SecureRandom;6
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import java.util.Arrays;8
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public class Main {11
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public static int binarySearch(int[] data, int key) {13
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int low = 0; // low end of the search area15
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int high = data.length - 1; // high end of the search area17
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int middle = (low + high + 1) / 2; // middle element19
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int location = -1; // return value; -1 if not found21
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do {24
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System.out.print(remainingElements(data, low, high));26
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for (int i = 0; i < middle; i++)29
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System.out.print(" ");// 来自 nowjava.com - 时代Java31
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System.out.println(" * "); // indicate current middle33
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// if the element is found at the middle36
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if (key == data[middle])38
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location = middle; // location is the current middle40
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else if (key < data[middle]) // middle element is too high42
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high = middle - 1; // eliminate the higher half44
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else46
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// middle element is too low48
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low = middle + 1; // eliminate the lower half50
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middle = (low + high + 1) / 2; // recalculate the middle53
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} while ((low <= high) && (location == -1));55
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return location;58
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}60
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private static String remainingElements(int[] data, int low, int high) {63
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StringBuilder temporary = new StringBuilder();65
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// append spaces for alignment68
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for (int i = 0; i < low; i++)70
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temporary.append(" ");72
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// append elements left in array75
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for (int i = low; i <= high; i++)77
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temporary.append(data[i] + " ");79
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return String.format("%s%n", temporary);82
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}84
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public static void main(String[] args) {87
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SecureRandom generator = new SecureRandom();89
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int[] data = new int[15]; // create array92
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for (int i = 0; i < data.length; i++)95
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// populate array97
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data[i] = 10 + generator.nextInt(90);99
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Arrays.sort(data); // binarySearch requires sorted array102
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