6. ZigZag Conversion-优快云博客

博客围绕字符串的之字形转换展开，给出示例字符串“PAYPALISHIRING”按指定行数转换的之字形排列及逐行读取结果，提出编写代码实现字符串转换的需求，还提及解题思路是找规律，即确定新字符串位置对应原字符串的位置。

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description:

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 s, int numRows);

Example:

Example 1:

Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"

Example 2:

Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:

P     I    N
A   L S  I G
Y A   H R
P     I

my answer:

就是找到现在这个string的这个位置应该填原来string的哪个

class Solution {
public:
    string convert(string s, int nRows) {
        if (nRows <= 1) return s;
        string res = "";
        int size = 2 * nRows - 2;
        for (int i = 0; i < nRows; ++i) {
            for (int j = i; j < s.size(); j += size) {
                res += s[j];
                int tmp = j + size - 2 * i;
                if (i != 0 && i != nRows - 1 && tmp < s.size()) res += s[tmp];
            }
        }
        return res;
    }
};