LeetCode 006 ZigZag Conversion - Java

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 text, int nRows);

convert("PAYPALISHIRING", 3) should return "PAHNAPLSIIGYIR".

 

定位：中等题

题意较好理解，将给的字符串Z型排列后，重新读取，可以发现每个字符出现的位置都是有规律的，对于n高度的Z型，出现在Z中同一位置的字符/((n-1)/2)的余数是相同的，这样不考虑n=1，如果为1新字符串是与原字符串相同的。

 

Java实现如下：

public class Solution {
    public String convert(String s, int numRows) {
        int len=s.length();
        if(numRows==1){
            return s;
        }
        int gay=numRows*2-2;
        StringBuffer stringBuffer=new StringBuffer();
        int j,h;
        j=0;
        while(j<len){
            stringBuffer.append(s.charAt(j));
            j+=gay;
        }
        for(int i=1;i<gay/2;i++){
            j=i;
            h=gay-i;
            while(j<len){
                stringBuffer.append(s.charAt(j));
                j+=gay;
                if(h<len){
                    stringBuffer.append(s.charAt(h));
                    h+=gay;
                }
            }
        }
        j=numRows-1;
        while(j<len){
            stringBuffer.append(s.charAt(j));
            j+=gay;
        }
        return stringBuffer.toString();
    }
}