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:建立numRows个数组分别记录每一行的字符串,遍历一遍字符串,将每个字符放在对应的数组中,遍历的顺序是先向下,在对角线,之后以此重复,最后将每一行的代码拼接起来即可,代码如下:
class Solution {
public:
string convert(string s, int numRows) {
if(numRows==1)
return s;
int len = s.length(),i = 0,j;
string *res = new string[numRows];
while(i < len){
for(j = 0; j < numRows && i < len; ++j)
res[j] += s[i++];
for(j = numRows - 2; j > 0 && i < len; j--)
res[j] += s[i++];
}
string ret = "";
for(i = 0; i < numRows; ++i)
ret +=res[i];
return ret;
}
};