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  • 【LeetCode】6. ZigZag Conversion

    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".

    创建nRows个char数组,将s按照0,1,2,...,nRows-2,nRows-1,nRows-2,...,2,1,0的顺序,

    将s中每个字符装入数组。

    具体来说,数组下标先递增,直到nRows-1,则反向,直到0,再反向,……直到s字符全部装入各数组

    再依次输出0~nRows-1个数组。

    class Solution {
    public:
        string convert(string s, int nRows) {
            if(nRows == 1)
                return s;
            string ret;
            vector<vector<char> > text(nRows, vector<char>());
            int tag = 1;    //1-ascend, -1-descend
            int ind = -1;
            for(int i = 0; i < s.size(); i ++)
            {
                ind += tag;
                text[ind].push_back(s[i]);
                if(ind == nRows-1)
                    tag = -1;   //reach the tail, turn back
                else if(ind == 0)
                    tag = 1;    //reach the head, turn back
            }
            for(int i = 0; i < nRows; i ++)
            {
                for(int j = 0; j < text[i].size(); j ++)
                    ret += text[i][j];
            }
            return ret;
        }
    };

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  • 原文地址:https://www.cnblogs.com/ganganloveu/p/4179226.html
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