[栈] leetcode 1019 Next Greater Node In Linked List

problem:https://leetcode.com/problems/next-greater-node-in-linked-list/

维护递减的单调栈。这道题对象是链表,不像数组可以快速通过下标索引,所以比较方便的做法是在栈中同时记录数字和对应的下标,并且默认填0,如果找到了比它大的第一个数,再修改下标对应的数字。

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    vector<int> nextLargerNodes(ListNode* head) {
        stack<pair<int,int>> sta;
        vector<int> res;
        int i = 0;
        ListNode* cur = head;
        while(cur)
        {
            while(!sta.empty() && cur->val > sta.top().first)
            {
                int idx = sta.top().second;
                sta.pop();
                res[idx] = cur->val;
            }
            sta.push({ cur->val, i++});
            res.push_back(0);
            cur = cur->next;
        }

        return res;
    }
};

原文地址:https://www.cnblogs.com/fish1996/p/11335303.html

时间: 2024-10-30 12:39:13

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