ucas_123的博客

Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.push(x) – Push element x onto stack. pop() – Removes the element on top of the stack. top() – Get the

Given two non-negative numbers num1 and num2 represented as string, return the sum of num1 and num2. 编程答案：class Solution {public: string addStrings(string num1, string num2) { if(num1.siz

struct ListNode{ int val; ListNode *next;};void printList(ListNode *head){ ListNode *p; p = head->next; while(p) { cout << p->val<<endl; p = p->next; }}

题目：Given an integer, write a function to determine if it is a power of two. 判断一个数是否是2的幂，如果是2的幂改善，这个数最高位是1，这个数减1，除最高位，其余都为零，利用这个特点，可以判断出是否是2的幂。class Solution {public: bool isPowerOfTwo(int n) {

题目：Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node with value

Given a list, rotate the list to the right by k places, where k is non-negative.For example: Given 1->2->3->4->5->NULL and k = 2, return 4->5->1->2->3->NULL. 题目要求：旋转链表，要主要k等于0及k大于链表长度的情况，可以通过取余就可以解决

题目：Reverse a singly linked list. 将链表反向输出，遍历链表，先遍历的后输出，最后遍历的先输出，实际上是一个栈的过程，利用栈实现。/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(in

Write an algorithm to determine if a number is “happy”.A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of i