Java字符串常见编程题

Z形排列字符串

Description
The string “PAYPALISHIRING” is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)

P A H N
A P L S I I G
Y I R
And then read line by line: “PAHNAPLSIIGYIR”

Write the code that will take a string and make this conversion given a number of rows:

string convert(string s, int numRows);
Example 1:

Input: s = “PAYPALISHIRING”, numRows = 3
Output: “PAHNAPLSIIGYIR”
Example 2:

Input: s = “PAYPALISHIRING”, numRows = 4
Output: “PINALSIGYAHRPI”
Explanation:

P I N
A L S I G
Y A H R
P I
Tags: String

	public String convert(String s, int numRows)
	{
		if(numRows <= 1)
			return s;
		int len = s.length();
		char[] chars = s.toCharArray();
		StringBuilder[] sbs = new StringBuilder[numRows];
		for(int i=0;i=1 && i

atoi

String to Integer (atoi)

import java.util.*;
import java.lang.Thread.State;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;

class Solution
{
	public static void main(String[] args) 
	{
		System.out.println(new Solution().myAtoi(" "));
	}
	
	public int myAtoi(String str)
	{
		if("".equals(str))
		{
			return 0; 
		}
		
		int i=0,sign=1,len=str.length();
		long ans = 0;
		
		//过滤空格		
		while(i 9)
				break;
			ans = ans * 10 +tmp;
			if( ans > Integer.MAX_VALUE)
			{
				if(sign == -1)
					return sign * (Integer.MAX_VALUE+1);
				else if (sign == 1)
					return sign * (Integer.MAX_VALUE);
			}
			
		}
		return (int)(sign * (int) ans);
		
	}
}