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leetcode6: zigzag conversion 2. Analysis 3. Solution(s)

admin 11月 12, 2020 0

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:

1	string convert(string text, int nRows);

convert(“PAYPALISHIRING”, 3) should return “PAHNAPLSIIGYIR”.

2. Analysis

ZigZag 即循环对角结构：

3. Solution(s)

class (object):
    def convert(self, s, numRows):
        """
        :type s: str
        :type numRows: int
        :rtype: str
        """
        if numRows == 1:
            return s
        rows = [""] * numRows
        k= 2 * numRows - 2
        for i, ch in enumerate(s):
            r = min(i%k, k-i%k)   
            rows[r] += ch
        res = ""
        for row in rows:
            res +=''.join(row)
        return res