将一个给定字符串根据给定的行数, 以从上往下, 从左到右进行 Z 字形排列.
比如输入字符串为 "LEETCODEISHIRING" 行数为 3 时, 排列如下:
- L C I R
- E T O E S I I G
- E D H N
之后, 你的输出需要从左往右逐行读取, 产生出一个新的字符串, 比如:"LCIRETOESIIGEDHN".
请你实现这个将字符串进行指定行数变换的函数:
string convert(string s, int numRows);
示例 1:
输入: s = "LEETCODEISHIRING", numRows = 3
输出: "LCIRETOESIIGEDHN"
示例 2:
输入: s = "LEETCODEISHIRING", numRows = 4
输出: "LDREOEIIECIHNTSG"
解释:
- L D R
- E O E I I
- E C I H N
- T S G
- public class Solution {
- public String convert(String s, int numRows) {
- if (numRows == 1) {
- return s;
- }
- List<StringBuilder> rows = new ArrayList<>();
- for (int i = 0; i < Math.min(numRows, s.length()); i++) {
- rows.add(new StringBuilder());
- }
- boolean goingDown = false;
- int curRow = 0;
- for (char c : s.toCharArray()) {
- rows.get(curRow).append(c);
- if (curRow == 0 || curRow == numRows - 1) {
- goingDown = !goingDown;
- }
- curRow += goingDown ? 1 : -1;
- }
- StringBuilder ret = new StringBuilder();
- for (StringBuilder row : rows) {
- ret.append(row);
- }
- return ret.toString();
- }
- }
来源: http://www.bubuko.com/infodetail-3329971.html