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SymmetricTree

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	`1`	`+/*`
	`2`	`+ Author: King, higuige@gmail.com`
	`3`	`+ Date: Dec 25, 2014`
	`4`	`+ Problem: Symmetric Tree`
	`5`	`+ Difficulty: Easy`
	`6`	`+ Source: https://oj.leetcode.com/problems/symmetric-tree/`
	`7`	`+ Notes:`
	`8`	`+ Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).`
	`9`	`+ For example, this binary tree is symmetric:`
	`10`	`+ 1`
	`11`	`+ / \`
	`12`	`+ 2 2`
	`13`	`+ / \ / \`
	`14`	`+ 3 4 4 3`
	`15`	`+ But the following is not:`
	`16`	`+ 1`
	`17`	`+ / \`
	`18`	`+ 2 2`
	`19`	`+ \ \`
	`20`	`+ 3 3`
	`21`	`+ Note:`
	`22`	`+ Bonus points if you could solve it both recursively and iteratively.`
	`23`	`+`
	`24`	`+ Solution: 1. Recursive solution`
	`25`	`+ */`
	`26`	`+`
	`27`	`+/**`
	`28`	`+ * Definition for binary tree`
	`29`	`+ * public class TreeNode {`
	`30`	`+ * int val;`
	`31`	`+ * TreeNode left;`
	`32`	`+ * TreeNode right;`
	`33`	`+ * TreeNode(int x) { val = x; }`
	`34`	`+ * }`
	`35`	`+ */`
	`36`	`+publicclassSolution {`
	`37`	`+publicbooleanisSymmetric(TreeNoderoot) {`
	`38`	`+if (root ==null)returntrue;`
	`39`	`+returnsolve (root.left,root.right);`
	`40`	`+ }`
	`41`	`+publicbooleansolve(TreeNodet1,TreeNodet2) {`
	`42`	`+if (t1 ==null &&t2 ==null)returntrue;`
	`43`	`+if (t1 ==null &&t2 !=null \|\|t1 !=null &&t2 ==null \|\|t1.val !=t2.val)returnfalse;`
	`44`	`+returnsolve(t1.left,t2.right) &&solve(t1.right,t2.left);`
	`45`	`+ }`
	`46`	`+}`

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