LeetCode #6 ZigZag Conversion

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 text, int nRows); convert(“PAYPALISHIRING”, 3) should return “PAHNAPLSIIGYIR”.

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Analysis

题目难度为：medium 这是一题数学题，看懂题目就好，所谓的Z排列就是如下这种形式：

1 7 1 9 2 6 8 2 8 0 3 5 9 3 7 A 4 0 4 6 B 5

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Code（c )

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