查找

哈哈，在程序里面，查找也是很重要的。下面给出简单的几种查找...

package net.itaem.search;

import java.util.Arrays;
import java.util.Random;

/**
 * 顺序查找
 * */
public class Search {

	private int[] search = new int[Integer.MAX_VALUE/32];
	private Random random = new Random();

	public Search(){
		for(int i=0; i<Integer.MAX_VALUE/32; i++){
			search[i] = i;
		}

	}

	//顺序查找
	//逐个遍历
	public int iterSearch(int key){
		for(int i=0; i<search.length; i++){
			if(search[i] == key){
				return i;
			}
		}

		//代表没有找到
		return -1;
	}

	//折半查找
	//前提条件：这个带查找集合是已经排序好的集合
	public int binarySearch(int key){

		//第一步：先排序带查找的数组，测试时，因为数据本身已经排序好了，不需要执行
		//Arrays.sort(search);
		int low = 0;  //低位
		int high = search.length - 1;   //高位

		int middle = -1;
		while(low < high){
			middle = (low + high)/2;
			int var = search[(low + high)/2];
			if(key > var){
				low = middle + 1;  //往大的方向移动一位
			}else if(key < var){
				high = middle;    //往小的方向移动一位
			}else{
				return middle;   //找到了直接返回
			}
		}

		return middle;
	}

	//插值查找
	//注意：是插值查找，不是插入排序
	public int interpolationSerach(int key){
		//前提条件：该集合数组排序好
		//第一步：先排序带查找的数组，测试时，因为数据本身已经排序好了，不需要执行
		//Arrays.sort(search);
		int low = 0;  //低位
		int high = search.length - 1;   //高位

		int middle = -1;
		while(low < high){
			middle = low + (high-low) * (search[high] - search[low]);   //优化middle...
			middle = (low + high)/2;
			int var = search[(low + high)/2];
			if(key > var){
				low = middle + 1;  //往大的方向移动一位
			}else if(key < var){
				high = middle;    //往小的方向移动一位
			}else{

				return middle;   //找到了直接返回
			}
		}

		return middle;
	} 

	public int fibonacciSearch(int key){
		return -1;
	}

	public static void main(String[] args) {
		Search search = new Search();

		System.out.println("=====================iterator search================");
		System.out.println(99999 + " in " + search.iterSearch(99999));

		System.out.println("=================binary serach=========================");
		System.out.println(99999 + " binary serach " + search.binarySearch(99999));

		System.out.println("=================interpolation serach=========================");
		System.out.println(99999 + " interpolation serach " + search.interpolationSerach(99999));

	}
}

查找