Same Tree @ LeetCode

/**
 * Same Tree
 * 
 * Given two binary trees, write a function to check if they are equal or not.
 * 
 * Two binary trees are considered equal if they are structurally identical and
 * the nodes have the same value.
 * 
 */
public class S100 {

	public static void main(String[] args) {
		
	}
	
	
	public boolean isSameTree(TreeNode p, TreeNode q) {
		// 如果同时为空，则相等
        if(p==null && q==null){
        	return true;
        }else if(p==null || q==null){	// 如果一个空一个不空，则不等
        	return false;
        }
        
        if(p.val == q.val){		// 如果节点值相等，继续检查p，q的左右子树
        	return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
        }else{
        	return false;
        }
    }

}