常见查找算法-JAVA实现

package org.nxt.algorithm.search;
/**
 * the bean of comparable
 * @author nanxiaotao
 *
 */
public class ComparableBean implements Comparable {

	private int value;
	

	public int getValue() {
		return value;
	}



	public void setValue(int value) {
		this.value = value;
	}



	@Override
	public int compareTo(ComparableBean o) {
		if(this.value

1.线性查找

   适用场景：顺序存储或链接存储的线性表

   时间复杂度:O(n)

package org.nxt.algorithm.search;


/**
 * linear search
 * @author nanxiaotao
 *
 */
public class LinearSearch {
	
	/**
	 * search
	 * @param datas aggregate of the data
	 * @param target the object to look for
	 * @return
	 */
	public static ComparableBean search(ComparableBean [] datas,ComparableBean target) {
		
		ComparableBean result=null;//Object found
		
		for(int i=0;i

1.二分查找

   适用场景：已经有序

   时间复杂度:O(log2n)

package org.nxt.algorithm.search;
/**
 * Binary Search
 * @author nanxiaotao
 *
 */
public class BinarySearch {
	
	/**
	 * search
	 * @param datas datas aggregate of the data
	 * @param target target the object to look for
	 */
	public static ComparableBean search(ComparableBean [] datas,ComparableBean target) {
		
		ComparableBean result=null;//Object found
		
		int first=0;//the first index of collection
		
		int last=datas.length-1;//the last index of collection
		
		int mid;//the middle index of colleciton
		
		/**
		 * Traverse the collection
		 * suspensive condition:
		 *                     1:find the target
		 *                     2:the first index equals the last index
		 */
		while(result==null&&first<=last) {
			mid=(first+last)/2;//compute the middle index
			if(datas[mid].compareTo(target)==0) {
				//equal
				result=datas[mid];
			}else {
				if(datas[mid].compareTo(target)==-1) {
					//smaller
					first=first+1;
				}else {
					//bigger
					last=last-1;
				}
			}
			
		}
		
		return result;
		
	}

}