Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).
For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should return 3.
常规思路，每次最低位与1，如果为1则右移一位，cnt++,如果......
You are climbing a stair case. It takes n steps to reach to the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
Note: Given n will be a positive integer.
int climbStairs(int n)
{
/*递归实现更好理解，但性能存在问题*/
if(n <= 0)
return 0;
if(1 == n)......
Given an unsorted array of integers, find the length of longest continuous increasing subsequence (subarray).
Example 1:
Input:
Output: 3
Explanation: The longest continuous increasing subsequence is [1,3,5], its length is 3.
Even though [1,3,5,7] is also an increasing subsequence, it'......
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.
/**
* Definition for singly-linked ......
Given a sorted linked list, delete all duplicates such that each element appear only once.
For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.
/**
* Definition for singly-linked list.
* struct ListNode
{
* int val;
* struct ListNo......
Implement pow(x, n).
Example 1:
Input: 2.00000, 10
Output: 1024.00000
Example 2:
Input: 2.10000, 3
Output: 9.26100
double myPow(double x, int n)
{
if(n == 0)
return 1.0;
if(n == 1)
return x;
long long int m = n > 0 ? n : -n;
double ans = x;
long long int cur = 1.0;
while(2 * cur &l......
Given two binary trees, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical and the nodes have the same value.
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* struct TreeNode *left;
* ......
Given two binary strings, return their sum (also a binary string).
For example,
a = "11"
b = "1"
Return "100".
char* addBinary(char* a, char* b)
{
int la = strlen(a);
int lb = strlen(b);
int lr = la > lb ? la : lb;
int carry = 0;
/*可能存在进位，计算前无法预判，多申请进位和\0*/......
Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.
实现思路：由于在LeetCode C实现 21. Merge two sorted Lists中我们已经完成了两个有序链表的合并，所以k个有序链表的合并可以依次合并，经过k-1次合并成一个链表。
实现代码如下：
方法一：
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* str......
Determine whether an integer is a palindrome. Do this without extra space.
click to show spoilers.
Some hints:
Could negative integers be palindromes? (ie, -1)
If you are thinking of converting the integer to string, note the restriction of using extra space.
You could also try reve......