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
Example 3:
Input: s = "A", numRows = 1
Output: "A"
Constraints:
- 1 <= s.length <= 1000
- s consists of English letters (lower-case and upper-case), ',' and '.'.
- 1 <= numRows <= 1000
class Solution {
public String convert(String s, int numRows) {
if(s==null||s.length()==0) return "";
char[] c = s.toCharArray();
StringBuffer[] sb = new StringBuffer[numRows];
for(int k =0;k<numRows;k++){
sb[k] = new StringBuffer();
}
int i = 0;
while(i<s.length()){
for(int idx = 0;idx<numRows&&i<s.length();idx++){
sb[idx].append(c[i++]);
}
for(int idx = numRows-2;idx>0&&i<s.length();idx--){
sb[idx].append(c[i++]);
}
}
for(int j=1;j<numRows;j++){
sb[0].append(sb[j]);
}
return sb[0].toString();
}
}