[leetcode]6. ZigZag Conversion(Java)

https://leetcode.com/problems/zigzag-conversion/#/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   NA P L S I I GY   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".

题意解析：

把给定的字符串进行重新排列，排成齿轮状。通过图像来解释会更直观

Java Code:

package go.jacob.day705;public class Demo3 {public String convert(String s, int numRows) {if (s == null || s.length() < numRows)return s;StringBuffer[] sb = new StringBuffer[numRows];for (int i = 0; i < numRows; i++) {sb[i] = new StringBuffer();}char[] c = s.toCharArray();int len = s.length();int index = 0;while (index < len) {for (int i = 0; i < numRows && index < len; i++) {sb[i].append(c[index++]);}for(int i=numRows-2;i>0&& index < len;i--){sb[i].append(c[index++]);}}for(int i=1;i<numRows;i++){sb[0].append(sb[i]);}return sb[0].toString();}}