84 lines
1.9 KiB
Java
84 lines
1.9 KiB
Java
package com.leetcode.string;
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import java.util.ArrayList;
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import java.util.List;
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/**
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*
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Z 字形变换:
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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。
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比如输入字符串为 "LEETCODEISHIRING" 行数为 3 时，排列如下：
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L C I R
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E T O E S I I G
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E D H N
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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"。
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请你实现这个将字符串进行指定行数变换的函数：
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string convert(string s, int numRows);
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示例 1:
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输入: s = "LEETCODEISHIRING", numRows = 3
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输出: "LCIRETOESIIGEDHN"
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示例 2:
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输入: s = "LEETCODEISHIRING", numRows = 4
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输出: "LDREOEIIECIHNTSG"
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解释:
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L D R
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E O E I I
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E C I H N
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T S G
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来源：力扣（LeetCode）
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链接：https://leetcode-cn.com/problems/zigzag-conversion
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著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。
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*
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* @author zeek
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*
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*/
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public class Convert2Zstr {
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public String convert(String s, int numRows) {
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if (numRows == 1) {
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return s;
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}
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List<StringBuilder> rows = new ArrayList<>();
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for (int i = 0; i < Math.min(numRows, s.length()); i++) {
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rows.add(new StringBuilder());
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}
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int curRow = 0;
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boolean goingDown = false;
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for (char c : s.toCharArray()) {
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rows.get(curRow).append(c);
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if (curRow == 0 || curRow == numRows - 1) goingDown = !goingDown;
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curRow += goingDown ? 1 : -1;
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}
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StringBuilder ret = new StringBuilder();
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for (StringBuilder row : rows) {
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ret.append(row);
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}
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return ret.toString();
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}
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public static void main (String args[]) {
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Convert2Zstr conv = new Convert2Zstr();
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String s = "LEETCODEISHIRING";
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int numRows = 4;
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String res = conv.convert(s, numRows);
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System.out.println(res);
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}
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}
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