Add ZigZag Conversion

Author: gahogg

Zigzag Conversion - Leetcode 6/Zigzag Conversion - Leetcode 6.cpp

@@ -0,0 +1,25 @@
+#include <string>
+#include <vector>
+
+class Solution {
+public:
+    std::string convert(const std::string& s, int numRows) {
+        if (numRows == 1) return s;
+
+        std::vector<std::string> rows(std::min(numRows, int(s.length())));
+        int i = 0;
+        bool goingDown = false;
+
+        for (char c : s) {
+            rows[i] += c;
+            if (i == 0 || i == numRows - 1) goingDown = !goingDown;
+            i += goingDown ? 1 : -1;
+        }
+
+        std::string result;
+        for (const std::string& row : rows) {
+            result += row;
+        }
+        return result;
+    }
+};

Zigzag Conversion - Leetcode 6/Zigzag Conversion - Leetcode 6.java

@@ -0,0 +1,25 @@
+public class Solution {
+    public String convert(String s, int numRows) {
+        if (numRows == 1) return s;
+
+        List<StringBuilder> rows = new ArrayList<>();
+        for (int i = 0; i < Math.min(numRows, s.length()); i++) {
+            rows.add(new StringBuilder());
+        }
+
+        int i = 0;
+        boolean goingDown = false;
+
+        for (char c : s.toCharArray()) {
+            rows.get(i).append(c);
+            if (i == 0 || i == numRows - 1) goingDown = !goingDown;
+            i += goingDown ? 1 : -1;
+        }
+
+        StringBuilder result = new StringBuilder();
+        for (StringBuilder row : rows) {
+            result.append(row);
+        }
+        return result.toString();
+    }
+}

Zigzag Conversion - Leetcode 6/Zigzag Conversion - Leetcode 6.js

@@ -0,0 +1,15 @@
+var convert = function(s, numRows) {
+    if (numRows === 1) return s;
+
+    let rows = Array.from({ length: Math.min(numRows, s.length) }, () => []);
+    let i = 0;
+    let goingDown = false;
+
+    for (let char of s) {
+        rows[i].push(char);
+        if (i === 0 || i === numRows - 1) goingDown = !goingDown;
+        i += goingDown ? 1 : -1;
+    }
+
+    return rows.flat().join('');
+};

Zigzag Conversion - Leetcode 6/Zigzag Conversion - Leetcode 6.py

@@ -0,0 +1,22 @@
+class Solution:
+    def convert(self, s: str, numRows: int) -> str:
+        if numRows == 1:
+            return s
+
+        i, d = 0, 1
+        rows = [[] for _ in range(numRows)]
+
+        for char in s:
+            rows[i].append(char)
+            if i == 0:
+                d = 1
+            elif i == numRows - 1:
+                d = -1
+            i += d
+
+        for i in range(numRows):
+            rows[i] = ''.join(rows[i])
+
+        return ''.join(rows)
+        # Time: O(n * numRows)
+        # Space: O(n)