题解 | #对称的二叉树#
对称的二叉树
http://www.nowcoder.com/practice/ff05d44dfdb04e1d83bdbdab320efbcb
/*
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
public class Solution {
boolean isSymmetrical(TreeNode pRoot) {
if(pRoot == null){
return true;
}
return isTrue(pRoot.left,pRoot.right);
return true;
return false;
return false;
}
}
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
public class Solution {
boolean isSymmetrical(TreeNode pRoot) {
if(pRoot == null){
return true;
}
return isTrue(pRoot.left,pRoot.right);
}
//前序遍历
boolean isTrue(TreeNode left ,TreeNode right){
//都为空返回true
if(left == null && right == null){return true;
}
//其中一个为空，返回false
if(left == null || right == null){return false;
}
//对称位置不相等，返回false
if(left.val!=right.val){return false;
}
return isTrue(left.left,right.right)&&isTrue(left.right,right.left); }
}
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