6.Zigzag Conversion.cpp

6.Zigzag Conversion.cpp

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+class Solution {
+public:
+    string convert(string s, int numRows) {
+        // Edge case: if numRows is 1 or greater than string length, return original string
+        if (numRows == 1 || numRows >= s.length()) {
+            return s;
+        }
+
+        // Create a vector to store characters for each row
+        vector<string> rows(numRows);
+
+        // Track current row and direction
+        int currentRow = 0;
+        bool goingDown = false;
+
+        // Iterate through each character in the string
+        for (char c : s) {
+            // Add character to current row
+            rows[currentRow] += c;
+
+            // Change direction when we hit top or bottom row
+            if (currentRow == 0 || currentRow == numRows - 1) {
+                goingDown = !goingDown;
+            }
+
+            // Move to next row based on direction
+            currentRow += goingDown ? 1 : -1;
+        }
+
+        // Concatenate all rows to get final result
+        string result;
+        for (string row : rows) {
+            result += row;
+        }
+
+        return result;
+    }
+};
+
+// Test cases
+#include <iostream>
+#include <vector>
+using namespace std;
+
+int main() {
+    Solution solution;
+
+    // Example 1
+    string s1 = "PAYPALISHIRING";
+    int numRows1 = 3;
+    cout << "Input: s = \"" << s1 << "\", numRows = " << numRows1 << endl;
+    cout << "Output: \"" << solution.convert(s1, numRows1) << "\"" << endl;
+    cout << "Expected: \"PAHNAPLSIIGYIR\"\n" << endl;
+
+    // Example 2
+    string s2 = "PAYPALISHIRING";
+    int numRows2 = 4;
+    cout << "Input: s = \"" << s2 << "\", numRows = " << numRows2 << endl;
+    cout << "Output: \"" << solution.convert(s2, numRows2) << "\"" << endl;
+    cout << "Expected: \"PINALSIGYAHRPI\"\n" << endl;
+
+    // Example 3
+    string s3 = "A";
+    int numRows3 = 1;
+    cout << "Input: s = \"" << s3 << "\", numRows = " << numRows3 << endl;
+    cout << "Output: \"" << solution.convert(s3, numRows3) << "\"" << endl;
+    cout << "Expected: \"A\"" << endl;
+
+    return 0;
+}