Leetcode 6. ZigZag Conversion（找规律，水题）

6. ZigZag Conversion

Medium

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 s, int numRows);

Example 1:

Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"

Example 2:

Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:

P     I    N
A   L S  I G
Y A   H R
P     I

(之字型）

 class Solution {
 public:
     string convert(string s, int numRows) {
         int len = s.length();
         string ans;
         if(numRows==) return s;
         for(int i = ;i < numRows; i++){
             int left = (numRows--i)*;
             int right = (i)*;
             int cnt = i;
             int flag = ;
             while(cnt < len){
                 flag = (flag+)%;
                 if((left== && flag==)||(right==&&flag==)) continue;
                 ans+=s[cnt];
                 if(flag==) cnt = cnt+left;
                 else cnt = cnt+right;
             }
         }
         return ans;
     }
 };