Zigzag Conversion Leetcode Solution
In this tutorial, we are going to solve zigzag conversion problem of leetcode in python.
Task
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 <= 1000sconsists of English letters (lower-case and upper-case),','and'.'.1 <= numRows <= 1000
Solution:
def convert(self, s: str, num_r: int) -> str:
n = len(s)
srt = [""] * num_r
if num_r == 1 or n == 1:
return s
row = 0
for i in range(n):
srt[row] += s[i]
if row == num_r - 1:
step = 1
elif row == 0:
step = 0
if step == 1:
row -= 1
else:
row += 1
return "".join(x for x in srt)
Steps
step1: first we made a list of length-given rows.
step2: then, we apply the base condition if the number of rows is 1 or the length of the string is 1.
step3: then we use the for loop and added the string elements in the same rows and update then accordingly.
step4: then we return the string by using the join function and apply it on the list.
