leetcode 6. ZigZag Conversion

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   NA P L S I I GY   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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数学方法拆分成row行,然后都按顺序接上

class Solution {public:string convert(string s, int numRows){if (s.length() <= 2 || numRows == 1)return s;else{   vector<string> str(numRows, "");  //字符串数组            for (int i = 0; i < s.size(); i++){int k = i % (2 * numRows - 2);if (k < numRows)str[k] = str[k] + s[i];elsestr[(2 * numRows - 2) - k] = str[(2 * numRows - 2) - k] + s[i];    }            string ret = "";for (int j = 0; j < numRows; j++)ret += str[j];return ret;}}};