# Zigzag Conversion Solution in C++ | LeetCode

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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 s, int numRows);
```

Example 1:

```Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"
```

Example 2:

```Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:
P     I    N
A   L S  I G
Y A   H R
P     I
```

Example 3:

```Input: s = "A", numRows = 1
Output: "A"
```

Constraints:

• `1 <= s.length <= 1000`
• `s` consists of English letters (lower-case and upper-case), `','` and `'.'`.
• `1 <= numRows <= 1000`

## Code in C++

``````class Solution {
public:
string convert(string s, int numRows) {
if (numRows == 1) return s;
string result;
int n = s.size();
int cycle = 2 * numRows - 2;
for (int i = 0; i < numRows; i++) {
for (int j = 0; j + i < n; j += cycle) {
result += s[j + i];
if (i != 0 && i != numRows - 1 && j + cycle - i < n)
result += s[j + cycle - i];
}
}
return result;
}

};``````