Zigzag Conversion in Java: Explanation & Practice

Convert string to zigzag pattern

Problem summary

Write a string in zigzag pattern on n rows, then read line by line.

Starter code

public class Main {
    public static void main(String[] args) {
        String str = "PAYPALISHIRING";
        int numRows = 3; // Test case 1
        
        // Convert to zigzag and print result
        // P   A   H   N
        // A P L S I I G
        // Y   I   R
        // Result: PAHNAPLSIIGYIR
    }
}

Expected output and test cases

3 rows zigzag
```
PAHNAPLSIIGYIR
```
4 rows zigzag
```
PINALSIGYAHRPI
```
1 row - no change
```
PAYPALISHIRING
```

Hints

Create array of StringBuilders for each row
Track current row and direction
Reverse direction at top and bottom rows

Related Strings exercises

Practice all Strings exercises · Run this idea in the Java compiler