本文共 1636 字,大约阅读时间需要 5 分钟。
二分查找:
二分查找又称折半查找,它是一种效率较高的查找方法。
二分查找要求:线性表是有序表,即表中结点按关键字有序,并且要用向量作为表的存储结构。不妨设有序表是递增有序的。
二分查找递归和非递归Java实现:
package com.algorithm.search;import com.algorithm.sort.BasicSort;public class BinarySearch { public static void main(String[] args) { int[] a={3,4,5,1,98,45,34,27,49,6,78}; int low=0; int high=a.length-1; int elem=45; BasicSort b=new BasicSort(); b.basicSort(a); for(int num:a){ System.out.print(" "+num); }// binarySearch(a,elem,low,high); directbinarySearch(a,elem,low,high); } /** *递归二分查找 */ public static int binarySearch(int[] a,int elem,int low,int high) { if (low <=high) { int mid = (low + high) / 2; if (a[mid] == elem) { System.out.println("递归二分查找找到该元素对应的下表:" + mid); return mid; } if (a[mid] > elem) { return binarySearch(a, elem, low, mid - 1); } if (a[mid] < elem) { return binarySearch(a, elem, mid + 1, high); } } return -1; } /** * 非递归二分查找 */ public static int directbinarySearch(int[] a,int elem,int low,int high) { while(low<=high){ int mid = (low + high) / 2; if(a[mid] == elem){ System.out.println("非递归二分查找找到该元素对应的下表:" + mid); return mid; } if (a[mid] > elem) { high=mid-1; } if(a[mid] < elem){ low=mid+1; } } return -1; }}输出: 1 3 4 5 6 27 34 45 49 78 98非递归二分查找找到该元素对应的下表:7
转载地址:http://irpqb.baihongyu.com/