题目讲解

6. Z 字形变换

算法讲解

class Solution {
public:
    string convert(string s, int numRows) {
        if(numRows == 1)return s;
        string ret;
        int step = 2 * numRows - 2;
        int n = s.size();
        //记录第一行
        for(int i = 0; i < n; i += step)
        {
            ret += s[i];
        }
        //处理接下来的行
        for(int i = 1; i < numRows - 1; i++)
        {
            for(int j = i, k = step-i; j < n || k < n; j += step, k += step)
            {
                if(j < n)ret += s[j];
                if(k < n)ret += s[k];
            }
        }
        //处理最后一行
        for(int i = numRows - 1; i < n; i += step)
        {
            ret += s[i];
        }
        return ret;
    }
};