ZigZag|ZigZag Conversion题目及解法

问题描述:

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)

PAHN A P L S I I G YIR

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" . 【ZigZag|ZigZag Conversion题目及解法】

大致思路,用空间换时间,看每一个字母放第几行,用step控制行数,当遍历完s时,把每一行的字符串连接起来即可得到答案。
代码如下:

if (numRows <= 1) return s; const int len = (int)s.length(); string *str = new string[numRows]; int row = 0, step = 1; for (int i = 0; i < len; ++i) { str[row].push_back(s[i]); if (row == 0) step = 1; else if (row == numRows - 1) step = -1; row += step; } s.clear(); for (int j = 0; j < numRows; ++j) { s.append(str[j]); } delete[] str; return s;


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