【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   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".

Solution:原来是说：

1      7

2   6 8

3 5   9

4 

要搞成折线图,然后横着输出.建nRows个数组，将s一个一个装进下标为0，1....nRows-1....1,0的数组里，两层vector

 class Solution {
 public:
     string convert(string s, int nRows) {
        if(nRows==)return s;
        vector<vector<char>> vec(nRows, vector<char>());

        int index=-;
        int tag=;
        for(int i=;i<s.size();i++){
            index += tag;
            vec[index].push_back(s[i]);
            if(index==nRows-)tag=-;
            else{
                if(index==)tag=;
            }
        }
        string ret;
        for(int i=;i<nRows;i++){
            for(int j=;j<vec[i].size();j++){
                ret+=vec[i][j];
            }
        }
        return ret;
     }
 };