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package Tree;

import java.util.ArrayList;

import java.util.LinkedList;

import java.util.List;

import java.util.Queue;

public class BuildTree {

/**

* Integer.MIN_VALUE表示为null

* @param input：以完全二叉树形式建立一棵树

* @param nullValue :空值表示

* @return 一棵树

*/

public static TreeNode buildTree(int[] input,int nullValue){

if(input.length==1) return new TreeNode(input[0]);

List<TreeNode> nodeList=new ArrayList<>();

for(int i=0;i<input.length;i++){

nodeList.add(new TreeNode(input[i]));

}

for(int i=1;i<=input.length/2;i++){

if(2*i-1<=input.length-1){

if(nodeList.get(2*i-1).val!=nullValue)

nodeList.get(i-1).left=nodeList.get(2*i-1);

else

nodeList.get(i-1).left=null;

}

if(2*i<=input.length-1){

if(nodeList.get(2*i).val!=nullValue)

nodeList.get(i-1).right=nodeList.get(2*i);

else

nodeList.get(i-1).right=null;

}

}

return nodeList.get(0);

}

}