#-*- coding: UTF-8 -*-#需要考虑多种情况#以下几种是可以返回的数值#1.以0开头的字符串,如01201215#2.以正负号开头的字符串,如'+121215':'-1215489'#3.1和2和空格混合形式[顺序只能是正负号-0,空格位置可以随意]的:'+00121515'#4.正数小于2147483647,负数大于-2147483648的数字#其他的情况都是返回0,因此在判断 是把上述可能出现的情况列出来,其他的返回0#AC源码如下class Solution(object…

#-*- coding: UTF-8 -*-#从前向后遍历罗马数字,#如果某个数比前一个数小,则加上该数.反之,减去前一个数的两倍然后加上该数###-----技术规则-----#-------------------------------------------------------------------------------------##1.相同的数字连写,所表示的数等于这些数字相加得到的数,例如:III = 3##2.小的数字在大的数字右边,所表示的数等于这些数字相加得到的数,例如…

题目String to Integer (atoi)(难度Medium) 大意是找出给定字串开头部分的整型数值,忽略开头的空格,注意符号,对超出Integer的数做取边界值处理. 方案1 class Solution { fun myAtoi(str: String): Int { val maxInt = " val maxIntS = "+2147483647" val minIntS = "-2147483648" val lengthMI = ma…

String to Integer (atoi) time=272ms   accepted 需考虑各种可能出现的情况 public class Solution { public int atoi(String str) { int length=str.length(); long result=0; int flag=1; Boolean bFlag=false,bSpace=false,bNum=false; if(length<=0) return (int) result; else…

一天一道LeetCode系列 (一)题目 Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases. Notes: It is intended for t…

#-*- coding: UTF-8 -*- #既然不能使用加法和减法,那么就用位操作.下面以计算5+4的例子说明如何用位操作实现加法:#1. 用二进制表示两个加数,a=5=0101,b=4=0100:#2. 用and(&)操作得到所有位上的进位carry=0100;#3. 用xor(^)操作找到a和b不同的位,赋值给a,a=0001:#4. 将进位carry左移一位,赋值给b,b=1000:#5. 循环直到进位carry为0,此时得到a=1001,即最后的sum.#!!!!!!关于负数的运算.…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 公众号:负雪明烛 本文关键词:字符串转整数,atoi,题解,Leetcode, 力扣,Python, C++, Java 目录 题目描述 题目大意 解题方法 代码 日期 题目地址:https://leetcode-cn.com/problems/string-to-integer-atoi/ 题目描述 Implement the myAtoi(string s) function, w…

题目: Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases. Notes: It is intended for this problem to be…

题目描述: Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases. Notes: It is intended for this problem to…

Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases. Notes: It is intended for this problem to be spe…

#-*- coding: UTF-8 -*-#2147483648#在32位操作系统中,由于是二进制,#其能最大存储的数据是1111111111111111111111111111111.#正因为此,体现在windows或其他可视系统中的十进制应该为2147483647.#32位数的范围是 -2147483648~2147483648class Solution(object):    def reverse(self, x):        """        :type…

class Solution(object):    def findAnagrams(self, s, p):        """        :type s: str        :type p: str        :rtype: List[int]        """        reslist=[];sdic={};pdic={}        ls=len(s)        lp=len(p)              …

#-*- coding: UTF-8 -*- class Solution(object):    def firstUniqChar(self, s):        s=s.lower()        sList=list(s)        numCdic={}        for c in s:            numCdic[c]=numCdic[c]+1 if c in numCdic else 1        for i in range(len(sList)):   …

#-*- coding: UTF-8 -*- #AC源码[意外惊喜,还以为会超时]class Solution(object):    def twoSum(self, nums, target):        """        :type nums: List[int]        :type target: int        :rtype: List[int]        """         for i in xrange(…

#-*- coding: UTF-8 -*-#利用strip函数去掉字符串去除空格(其实是去除两边[左边和右边]空格)#利用split分离字符串成列表class Solution(object):    def lengthOfLastWord(self, s):        """        :type s: str        :rtype: int        """        if s==None:return 0     …

#-*- coding: UTF-8 -*- # ord(c) -> integer##Return the integer ordinal of a one-character string.##参数是一个ascii字符,返回值是对应的十进制整数class Solution(object):    def titleToNumber(self, s):        columns=0        n=len(s)        s=s.upper()[::-1]        for c…

Problem Link: http://oj.leetcode.com/problems/interleaving-string/ Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example, Given: s1 = "aabcc", s2 = "dbbca", When s3 = "aadbbcbcac", return t…

#-*- coding: UTF-8 -*-# The isBadVersion API is already defined for you.# @param version, an integer# @return a bool# def isBadVersion(version):class Solution(object):    def firstBadVersion(self, n):        """        :type n: int        :…

#-*- coding: UTF-8 -*- class Solution:    # @param n, an integer    # @return an integer    def reverseBits(self, n):        tmp=str(bin(n))[2:][::-1]                for i in xrange(32-len(tmp)):            tmp+='0'               return int(tmp,base=…

深度优先搜索 # Definition for a binary tree node.# class TreeNode:#     def __init__(self, x):#         self.val = x#         self.left = None#         self.right = Noneclass Solution:    # @param {TreeNode} root    # @return {string[]}        resultList=[…

class Solution:      # @param digits, a list of integer digits      # @return a list of integer digits      def plusOne(self, digits):                carry=1                 for i in range(len(digits)-1,-1,-1):            digits[i]+=carry           …

Scramble String Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively. Below is one possible representation of s1 = "great": great / \ gr eat / \ / \ g r e at / \ a t To scramble the s…

#-*- coding: UTF-8 -*-class Solution(object):    def compareVersion(self, version1, version2):        """        :type version1: str        :type version2: str        :rtype: int        """        versionl1=version1.split('.'…

class Solution(object):    def convertToTitle(self, n):        """        :type n: int        :rtype: str        """        res=''        while n>0:            tmp=n            n=(n-1)/26            res+=chr(65+(tmp-1)%26)…

#-*- coding: UTF-8 -*-#由于题目要求不返回任何值,修改原始列表,#因此不能直接将新生成的结果赋值给nums,这样只是将变量指向新的列表,原列表并没有修改.#需要将新生成的结果赋予给nums[:],才能够修改原始列表class Solution(object):    def rotate(self, nums, k):        """        :type nums: List[int]        :type k: int        :…

#-*- coding: UTF-8 -*- class MinStack(object):    def __init__(self):        """        initialize your data structure here.        """        self.Stack=[]        self.minStack=[]            def push(self, x):        "&…

#-*- coding: UTF-8 -*- class Solution(object):    def isPalindrome(self, s):        """        :type s: str        :rtype: bool        """        s=s.lower()        if s==None:return False        isPalindrome1=[]        isPal…

#-*- coding: UTF-8 -*- #ZigZag Conversion :之字型class Solution(object):    def convert(self, s, numRows):        """        :type s: str        :type numRows: int        :rtype: str        """        if numRows==1:return s     …

#-*- coding: UTF-8 -*- #Tags:dynamic programming,sumRange(i,j)=sum(j)-sum(i-1)class NumArray(object):    sums=[]    def __init__(self, nums):        """        initialize your data structure here.        :type nums: List[int]        "&…

#-*- coding: UTF-8 -*- #Hint1:#数字i,i的倍数一定不是质数,因此去掉i的倍数,例如5,5*1,5*2,5*3,5*4,5*5都不是质数,应该去掉#5*1,5*2,5*3,5*4 在数字1,2,3,4的时候都已经剔除过,因此数字5,应该从5*5开始#Hint2:#例:#2 × 6 = 12#3 × 4 = 12#4 × 3 = 12#6 × 2 = 12#显然4 × 3 = 12,和6 × 2 = 12不应该分析,因为在前两式中已经知道12不是质数,因此如果数字i是…