Leetcode 6 Zigzag Conversion Solution in Java | Hindi Coding Community

 

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

Java Code :

public String convert(String s, int nRows) {

char[] c = s.toCharArray();

int len = c.length;

StringBuffer[] sb = new StringBuffer[nRows];

for (int i = 0; i < sb.length; i++) sb[i] = new StringBuffer();

int i = 0;

while (i < len) {

for (int idx = 0; idx < nRows && i < len; idx++)

sb[idx].append(c[i++]);

for (int idx = nRows-2; idx >= 1 && i < len; idx--)

sb[idx].append(c[i++]);

}

for (int idx = 1; idx < sb.length; idx++)

sb[0].append(sb[idx]);

return sb[0].toString();

}