leetcode第六题 ZigZag Conversion (java)
ZigZag Conversion
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 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"
.思路:列输入-->行输出,将zigzag字符串看成是字符数组,为空的位置其值为null
先确定数组的列数(nRows即为数组的行数)
time=440ms accepted
public class Solution { public String convert(String s, int nRows) { int length=s.length(); if(length<=nRows||nRows==1) return s; int updown=0,i=0,j=1,count=0,nLines=0; while(count<length){ if(updown==0){ if(i>nRows-1){ updown=nRows-1; i=nRows-2; }else{ count++; i++; } } if(updown==nRows-1){ if(i<1){ updown=0; i=0; j++; }else{ count++; i--; j++; } } } nLines=j; System.out.println("j="+j); char[][] zigzag=new char[nRows][nLines]; updown=0;i=0;j=0;count=0; while(count<length){ if(updown==0){ if(i>nRows-1){ updown=nRows-1; i=nRows-2; j++; }else{ zigzag[i][j]=s.charAt(count); count++; i++; } } if(updown==nRows-1){ if(i<1){ updown=0; i=0; }else{ zigzag[i][j]=s.charAt(count); count++; i--; j++; } } } StringBuffer sb = new StringBuffer(); for(int m=0;m<nRows;m++) for(int n=0;n<nLines;n++){ if(zigzag[m][n]!='\0'){ sb.append(String.valueOf(zigzag[m][n])); } } return sb.toString(); } }