chuandalishuo的博客

1. Java In-place solution: public class Solution { public String convert(String s, int numRows) { if(numRows=s.length()) return s; StringBuilder sb = new StringBuilder();

1. Java 2. Python class Solution(object): def reverse(self, x): """ :type x: int :rtype: int """ flag=1 if x<0: x=x*(-1)

1. Java public class Solution { public boolean isPalindrome(int x) { if(x<0) return false; return x==reverse(x); } public int reverse(int x) { long sum=0;

题目： Divide two integers without using multiplication, division and mod operator. If it is overflow, return MAX_INT. Java public class Solution { public int divide(int dividend, int divisor) {

题目： Given an integer n, return the number of trailing zeroes in n!. Note: Your solution should be in logarithmic time complexity. 思路：每包含一个5，结尾就有一个0. 25=5x5 算两个5，125＝5x5x5算三个5. Java：

Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If the fractional part is repeating, enclose the repeating part in parentheses.

Find the total area covered by two rectilinear rectangles in a 2D plane. Each rectangle is defined by its bottom left corner and top right corner as shown in the figure. Assume that the tota

Description: Count the number of prime numbers less than a non-negative number, n. 思路： 从前向后扫描，第一次遇到没标记的应该是没有因子的质数。然后把后面所有这个质数的倍数都标记了。 public int countPrimes(int n) { if(n<2) retur

Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -. Example: Given a = 1 and b = 2, return 3. 思路：a^b异或等于无进位的加法，(a&b) 解法一： public class Solution {