6.Zigzag Conversion.cpp

[devkumar2313]

Approach

The solution simulates writing the input string in a zigzag pattern across the specified number of rows and then reads it row by row to produce the final output.

• If numRows is 1 or greater than or equal to the string length, return the input string as is (edge cases).
• Use a vector of strings to represent each row in the zigzag pattern.
• Iterate through the string, placing each character in the appropriate row while tracking the current direction (down or up).
• Change direction when reaching the top or bottom row.
• Concatenate all rows to form the final result string.

Intuition

The zigzag pattern can be visualized as filling rows downwards and then diagonally upwards. The traversal of the string simulates this pattern, ensuring that each character is placed in the correct row. By storing characters row-wise and then concatenating, we can reconstruct the zigzagged string as required.

Solution in Code (C++)

class Solution {
public:
    string convert(string s, int numRows) {
        if (numRows == 1 || numRows >= s.length()) return s;
        vector<string> rows(numRows);
        int currRow = 0, direction = -1;
        for (char c : s) {
            rows[currRow] += c;
            if (currRow == 0 || currRow == numRows - 1) direction *= -1;
            currRow += direction;
        }
        string result;
        for (string& row : rows) result += row;
        return result;
    }
};

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Closes #38

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[devkumar2313]

is that right

[SjxSubham]

@devkumar2313 yes,,, all good

Star the Repo ⭐

Happy HAcktober... keep contributing

[devkumar2313]

I have star the repo