LeetCode 872. Leaf-Similar Trees

时间:2022-06-13
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872.Leaf-Similar Trees

Consider all the leaves of a binary tree.  From left to right order, the values of those leaves form a leaf value sequence.

For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).

Two binary trees are considered leaf-similar if their leaf value sequence is the same.

Return true if and only if the two given trees with head nodes root1 and root2 are leaf-similar.

Note:

  • Both of the given trees will have between 1 and 100 nodes.

题目大意:判断两个树的叶子节点是否相同

解题思路:本体属于简单题,将两个树的叶子节点都取出来,然后一一对比

解法:

public boolean leafSimilar(TreeNode root1, TreeNode root2) {
    List<Integer> list1 = new LinkedList<>();
    list1 = leafSequence(root1,list1);
    List<Integer> list2 = new LinkedList<>();
    list2 = leafSequence(root2,list2);
    
    if (list1.size()!=list2.size()) return false;
    for (int i = 0 ; i < list1.size();i++){
        if (list1.get(i) != list2.get(i)) return false;
    }
    return true;
}

public List<Integer> leafSequence(TreeNode root,List<Integer> list){
    if (root == null) return null;
    if (root.left == null && root.right == null) list.add(root.val);
    leafSequence(root.left,list);
    leafSequence(root.right,list);
    return list;
}