查找

package 无序表查找;public class 顺序表查找算法Test {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubint array[] = new int[]{0,1,2,3,4,5};System.out.println(new 顺序表查找算法Test().Sequential_Search2(array,4));}//int Sequential_Search(int [] array,int key){if(array == null || array.length <1) return -1;for(int i = 0;i<array.length;i++){if(key == array[i]) return i;}return -1;}//顺序查找的改进  可改变顺序表的结构int Sequential_Search2(int [] array,int key){if(array == null || array.length <1 ) return -1;if(array[0] == key) return 0;array[0]=key;//哨兵int i = array.length-1;while(array[i] != key){//免去了每次循环时候都要检查是否越界的判断i--;}if(i == 0) return -1;else return i;}}

package 有序表查找;public class 折半查找Test {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stub}//array升序int Binary_Search(int [] array,int key){if(array == null || array.length < 1) return 0;int start = 0;int end = array.length-1;int mid = 0;while(start <= end){mid=(start+end)/2;if( array[mid] == key) return mid;else if(array[mid] > key) end = mid-1;else start=mid+1;}return -1;}}

package 二叉排序树;public class BST{BinaryTreeNode root;public BST(BinaryTreeNode root){this.root = root;}public boolean SearchBST(int key){return SearchBST(root,key);}private boolean SearchBST(BinaryTreeNode node,int key){if(node == null) return false;if(node.val == key){return true;}else if(node.val < key){return SearchBST(node.right,key);}else{return SearchBST(node.left,key);}}public boolean InsertBST(int key){if(SearchBST(key)) {System.out.println("key已经存在于此二叉树中");return false;}return InsertBST(this.root,key);}private boolean InsertBST(BinaryTreeNode node,int key){if(node.val < key){if(node.right == null){BinaryTreeNode n = new BinaryTreeNode(key);node.right = n;return true;}else{return InsertBST(node.right,key);}}else{if(node.left == null){BinaryTreeNode n = new BinaryTreeNode(key);node.left = n;return true;}else{return InsertBST(node.left,key);}}}public boolean DeleteBST(int key){if(!SearchBST(key)) {System.out.println("不存在此结点，无法进行删除操作");return false;}return DeleteBST(this.root,null,key);}private boolean DeleteBST(BinaryTreeNode node,BinaryTreeNode parent,int key){if(node.val < key) return DeleteBST(node.right,node,key);else if(node.val > key) return DeleteBST(node.left,node,key);else{if(node.left == null && node.right == null){//叶子结点if(node == root){//只有一个根结点this.root=null;return true;}else{if(parent.left == node) parent.left = null ;else parent.right = null;node=null;return true;}}else if(node.left == null && node.right != null){//左子树为空if(parent.left == node)  parent.left = node.right;else parent.right = node.right;node = null;return true; }else if(node.left != null && node.right == null){//右子树为空if(parent.left == node)  parent.left = node.left;else parent.right = node.left;node = null;return true; }else{//左右子树均不为空BinaryTreeNode temp = node.right;BinaryTreeNode q = node;while(temp.left != null){q=temp;temp=temp.left;}int t = temp.val;temp.val=node.val;node.val=t;return DeleteBST(temp,q,key);}}}public static void main(String[] args) {BinaryTreeNode root = new BinaryTreeNode(62);BST tree = new BST(root);/*tree.InsertBST(58);tree.InsertBST(88);tree.InsertBST(47);tree.InsertBST(73);tree.InsertBST(99);tree.InsertBST(93);tree.InsertBST(102);*//*System.out.println(tree.SearchBST(88));System.out.println(tree.SearchBST(47));System.out.println(tree.SearchBST(99));System.out.println(tree.SearchBST(58));System.out.println(tree.SearchBST(93));*///System.out.println(tree.DeleteBST(102));System.out.println(tree.root);System.out.println(tree.DeleteBST(62));System.out.println(tree.root);/*System.out.println(tree.root);System.out.println(tree.removeBST(62));System.out.println(tree.root);*/}}

/* * 二叉树结点 * */public class BinaryTreeNode {int val;BinaryTreeNode left;BinaryTreeNode right;public BinaryTreeNode(int val){this.val=val;}@Overridepublic String toString() {return "BinaryTreeNode [val=" + val + ", left=" + left + ", right="+ right + "]";}}