LeetCode 6 ZigZag Conversion-优快云博客

本文介绍了一种将字符串以Z形排列方式写入多行再逐行读取的方法，并提供了一个具体的Java实现案例。该算法适用于任何给定的行数，通过模拟人眼观察过程来生成每行的字符串，最后将所有行的字符串拼接成最终结果。

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   R

And 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：模拟人生成每行的字符串，然后把每行的字符串拼接起来即可。

public class Solution {
	public String convert(String s, int nRows) {
		if (nRows == 1 || s.length() == 0)
			return s;
		boolean flag = false;// 标记生产字符的方向

		StringBuffer[] sb = new StringBuffer[nRows];
		for (int i = 0; i < nRows; i++)
			sb[i] = new StringBuffer("");

		for (int i = 0, j = 0; i < s.length(); i++) {
			sb[j].append(s.charAt(i));
			if (j == nRows - 1)
				flag = true;
			else if (j == 0)
				flag = false;
			if (!flag)
				j++;
			else
				j--;
		}

		for (int i = 1; i < nRows; i++)
			sb[0].append(sb[i]);

		return sb[0].toString();
	}
}