Question Definition
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”.
Java Solution
public String convert(String s, int numRows) {
char[] c = s.toCharArray();
int len = c.length;
StringBuffer[] sb = new StringBuffer[numRows];
for (int i = 0; i < sb.length; i++) sb[i] = new StringBuffer();
int i = 0;
while (i < len) {
for (int idx = 0; idx < numRows && i < len; idx++) // vertically down
sb[idx].append(c[i++]);
for (int idx = numRows-2; idx >= 1 && i < len; idx--) // obliquely up
sb[idx].append(c[i++]);
}
for (int idx = 1; idx < sb.length; idx++)
sb[0].append(sb[idx]);
return sb[0].toString();
}
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