题解 | #重建二叉树#
重建二叉树
http://www.nowcoder.com/practice/8a19cbe657394eeaac2f6ea9b0f6fcf6
代码:
写着写着就会忘记break;
在Idea里面写的时候注意自定义TreeNode。
public static TreeNode reConstructBinaryTree(int[] pre, int[] vin) {
if(pre.length ==0 || vin.length == 0){
return null;
}
TreeNode root = new TreeNode(pre[0]);
for (int i = 0; i < vin.length; i++) {
if(vin[i] == pre[0]){
root.left = reConstructBinaryTree(Arrays.copyOfRange(pre,1,i+1),Arrays.copyOfRange(vin,0,i));
root.right = reConstructBinaryTree(Arrays.copyOfRange(pre,i+1,pre.length),Arrays.copyOfRange(vin,i+1,vin.length));
break;
}
}
return root;
}