package leetCode_6;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Map;

/**

* @author dimdark

* @date 2017-04-21

* @time 3:51 PM

*/

public class Solution {

public String convert(String s, int rowsLength) {

if (rowsLength==1){

return s;

}

Map<Integer,ArrayList<Character>> map = new HashMap<Integer,ArrayList<Character>>();

//初始化map

for (int i=0; i<rowsLength; ++i){

map.put(i,new ArrayList<Character>());

}

//flag为true表示index递增(向下移动),为false表示index递减(向上移动)

boolean flag = true;

int index = 0; //用来取得对应行数的字符数组

for (int i=0; i<s.length(); ++i){

ArrayList<Character> chars = map.get(index);

chars.add(s.charAt(i));

index = flag?(index+1):(index-1);

if(index==rowsLength){

index -= 2;

flag = false;

}

if (index==-1){

index += 2;

flag = true;

}

}

//将结果转换为字符串

StringBuffer buffer = new StringBuffer();

for (int i=0; i<rowsLength; ++i){

ArrayList<Character> chars = map.get(i);

for (char c:chars){

buffer.append(c);

}

}

return buffer.toString();

}

}