题解 | #二叉搜索树与双向链表#

//史上最差代码 /** public class TreeNode { int val = 0; TreeNode left = null; TreeNode right = null;

public TreeNode(int val) {
    this.val = val;

}

} */ import java.util.LinkedList; import java.util.List;

public class Solution { List list = new LinkedList<>();

public TreeNode Convert(TreeNode pRootOfTree) {
    if(pRootOfTree == null) return null;
    if(pRootOfTree.left==null && pRootOfTree.right==null) return pRootOfTree;
	
    dfs(pRootOfTree);
    for(int i = 0;i < list.size();i++) {
    	if(i == 0) {
    		list.get(0).right = list.get(1);
    		continue;
    	}
    	if(i == list.size() - 1) {
    		list.get(i).left = list.get(i-1);
    		continue;
    	}
    	
    	list.get(i).left = list.get(i-1);
    	list.get(i).right = list.get(i+1);
    }
    
	
	return list.get(0);
}

public void dfs(TreeNode tree) {
	if(tree == null) return;
	
	dfs(tree.left);
	list.add(tree);
	dfs(tree.right);
}

}