6.ZigZag Conversion(Graph, traverse)
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"
.
思路:图的遍历,先纵向,再横向。
图用string数组存储。
如果nRows=4,注意短的那列是倒序。
P I N
A L S I G
Y A H R
P I
如果nRows=2,全部是正序。
P Y ...
A P ...
class Solution { public: string convert(string s, int numRows) { string sArray[numRows]; int pChar = 0; //pointer to s int pRow = 0; //pointer to indicate row number while(1){ pRow = 0; while(pRow < numRows && pChar != s.length()){ //traverse first colomn sArray[pRow++] += s[pChar++]; } if(pChar == s.length()) return getReturnStr(sArray,numRows); pRow = numRows-2; while(pRow > 0 && pChar != s.length()){ sArray[pRow--] += s[pChar++]; } if(pChar == s.length()) return getReturnStr(sArray,numRows); } } string getReturnStr(string* sArray, int numRows){ string ret = ""; for(int i = 0; i < numRows; i++){ ret += sArray[i]; } return ret; } };