https://leetcode.com/problems/basic-calculator/ C++代码如下: 1classSolution {2public:3intevalRPN(vector<string>&tokens) {4stack<int>st;5if(tokens.size()==1)returnstoi(tokens[0]);6for(inti=0;i<tokens.size();i++){7if
LeetCode——150. Evaluate Reverse Polish Notation 一.题目链接:https://leetcode.com/problems/evaluate-reverse-polish-notation/ 二.题目大意: 给定后缀表达式,求出该表达式的计算结果。 三.题解: 对于这道题目,首先观察后缀表达式(逆波兰表达式)的特点,那就是运算符在操作数的后面,所以每遇到一个运算符,只需...
https://leetcode.cn/problems/number-of-ways-to-reconstruct-a-tree 这道题曾经在周赛难度分top1呆了几年,如今已经不在难度分top5了。破局的关键是父节点的邻居数肯定不少于子节点,而根节点的邻居数一定是n-1。所以应该先找到根节点,然后逐层向下建树,子节点的邻居一定是父节点的子集,否则就是非法;如果子...
class MinStack { /* * 思路：每次入栈2个元素，一个是入栈的元素本身，一个是当前栈元素的最小值 * 如：入栈序列为2-3-1，则入栈后栈中元素序列为：2-2-3-2-1-1 * 用空间代价来换取时间代价 */ private Stack stack;幽默
LeetCode:https://leetcode.com/problems/merge-intervals/ [4] 张安宇:https://blog.csdn.net/mobanchengshuang [5] 戴铭:https://ming1016.github.io [6] 展菲:https://github.com/fanbaoying [7] 倪瑶:https://github.com/niyaoyao [8]
☕ 题目:225. 用队列实现栈 (https://leetcode-cn.com/problems/implement-stack-using-queues/) ❓ 难度:简单 📕 描述: 请你仅使用两个队列实现一个后入先出(LIFO)的栈,并支持普通栈的全部四种操作(push、top、pop和empty)。 实现MyStack类: ...
Runtime:O(nlogn)- we loop all item in items, for each item, we perform the action of inserting the score into a heap tree. The worst time to insert a value in a heap tree isO(logn). Notice that the step when we heap pop 5 top scores from the heap, the time counts as constant...
215. 数组中的第K个最大元素 - 给定整数数组 nums 和整数 k,请返回数组中第 k 个最大的元素。 请注意,你需要找的是数组排序后的第 k 个最大的元素,而不是第 k 个不同的元素。 你必须设计并实现时间复杂度为 O(n) 的算法解决此问题。 示例 1: 输入: [3,2,1,5,6,4]
targetSum.py previous problems Apr 12, 2021 Repository files navigation README LeetCode Collection of LeetCode questions to ace the coding interview! - Created using LeetHub.About JavaScript Solution of Blind75, Neet150, Grind75 & other important LeetCode questions Topics javascript leetcode interv...
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