leetcode#6-ZigZag Conversion-java

题目：

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   RAnd 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".

解法一：

public String convert(String s, int numRows) {   StringBuilder [] sb = new StringBuilder[numRows];   int length = s.length();   for(int i=0;i<numRows;i++){       sb[i] = new StringBuilder();   }   char[] arr = s.toCharArray();   int i = 0;   while(i<length){       for(int dex = 0;dex<numRows && i<length;dex++){           sb[dex].append(arr[i++]);       }       for(int dex = numRows-2;dex>=1 && i<length;dex--){           sb[dex].append(arr[i++]);       }   }   for(int j=1;j<numRows;j++){       sb[0].append(sb[j]);   }   return sb[0].toString();}

解法二：

 public String convert(String s, int numRows) {    StringBuilder [] sb = new StringBuilder[numRows];    int length = s.length();    for(int i=0;i<numRows;i++){        sb[i] = new StringBuilder();    }    char[] arr = s.toCharArray();    int incre = 1;    int index = 0;    for(int i=0;i<length;i++){        sb[index].append(arr[i]);        if(index==0){            incre=1;        }        if(index==numRows-1){            incre = -1;        }        index+=incre;    }    for(int i=1;i<numRows;i++){        sb[0].append(sb[i]);    }    return sb[0].toString();}