LeetCode:ZigZag Conversion

6. ZigZag Conversion

Total Accepted: 78774 Total Submissions: 335842 Difficulty: Easy

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".

算好每行的间隔数。注意字符串长度为1的情况。

class Solution {
public:
    string convert(string s, int numRows) {
        if (numRows == 1) return s;
        string res = "";
        int i, j;
        int interval = 2 * numRows - 2;
        for (i = 0; i<s.length();)
        {
            res = res + s[i];
            i = i + interval;
        }
        
        for (j = 1; j<numRows - 1; j++)
        {
            int inter = 2 * j;
            for (i = j; i<s.length(); i = i + inter)
            {
                res = res + s[i];
                inter = interval - inter;
            }
        }
        for (i = numRows - 1; i<s.length();)
        {
            res = res + s[i];
            i = i + interval;
        }
        return res;
    }
};