LeetCode ZigZag Conversion

题目

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   NA P L S I I GY   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".

“zigzag”实际上是按"N"字镜像形状排布的，

可以获取横向数之间差的规律，然后直接合成结果

 

代码

class Solution {public:    string convert(string s, int nRows) {if(nRows==1)return s;        string ans;int len=s.size();int i,j,k;//处理到的行数，处理到的s中的序号，奇偶标志int d[2];//横向两个数的差for(i=0;i<nRows;i++){if(i==0||i==nRows-1){d[0]=2*(nRows-1);d[1]=2*(nRows-1);}else{d[0]=2*(nRows-1-i);d[1]=2*i;}j=i;k=0;while(j<len){ans+=s[j];j+=d[k];k=(k+1)&0x1;}}return ans;    }};