LeetCode（剑指 Offer）- 33. 二叉搜索树的后序遍历序列

Posted 2022-06-04 放羊的牧码

题目链接：点击打开链接

题目大意：略

解题思路

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AC 代码

• Java

class Solution 
    public boolean verifyPostorder(int[] postorder) 
        return recur(postorder, 0, postorder.length - 1);
    
    boolean recur(int[] postorder, int i, int j) 
        if(i >= j) return true;
        int p = i;
        while(postorder[p] < postorder[j]) p++;
        int m = p;
        while(postorder[p] > postorder[j]) p++;
        return p == j && recur(postorder, i, m - 1) && recur(postorder, m, j - 1);
    

• C++

class Solution 
public:
    bool verifyPostorder(vector<int>& postorder) 
        return recur(postorder, 0, postorder.size() - 1);
    
private:
    bool recur(vector<int>& postorder, int i, int j) 
        if(i >= j) return true;
        int p = i;
        while(postorder[p] < postorder[j]) p++;
        int m = p;
        while(postorder[p] > postorder[j]) p++;
        return p == j && recur(postorder, i, m - 1) && recur(postorder, m, j - 1);
    
;