1427-Perform-String-Shifts.py

'''
You are given a string s containing lowercase English letters, and a matrix shift, where shift[i] = [direction, amount]:

direction can be 0 (for left shift) or 1 (for right shift). 
amount is the amount by which string s is to be shifted.
A left shift by 1 means remove the first character of s and append it to the end.
Similarly, a right shift by 1 means remove the last character of s and add it to the beginning.
Return the final string after all operations.

 

Example 1:

Input: s = "abc", shift = [[0,1],[1,2]]
Output: "cab"
Explanation: 
[0,1] means shift to left by 1. "abc" -> "bca"
[1,2] means shift to right by 2. "bca" -> "cab"
Example 2:

Input: s = "abcdefg", shift = [[1,1],[1,1],[0,2],[1,3]]
Output: "efgabcd"
Explanation:  
[1,1] means shift to right by 1. "abcdefg" -> "gabcdef"
[1,1] means shift to right by 1. "gabcdef" -> "fgabcde"
[0,2] means shift to left by 2. "fgabcde" -> "abcdefg"
[1,3] means shift to right by 3. "abcdefg" -> "efgabcd"
 

Constraints:

1 <= s.length <= 100
s only contains lower case English letters.
1 <= shift.length <= 100
shift[i].length == 2
0 <= shift[i][0] <= 1
0 <= shift[i][1] <= 100
'''
# Method 1: Input in the form of string
class Solution:
    def stringShift(self, s: str, shift: List[List[int]]) -> str:
        direction = 0
        for amount in shift:
            if not amount[0]:
                direction -= amount[1]
            else:
                direction += amount[1]
        direction %= len(s)
        if direction > 0:
            return s[-direction:] + s[:-direction]
        elif direction < 0:
            return s[-direction:] + s[:-direction]
        else:
            return s

# Method 2: Input in the form of list
class Solution:
    def stringShift(self, s: str, shift: List[List[int]]) -> str:
        s_list = [i for i in s] #Changing String to List and carrying out
        for i in range(len(shift)):
            if shift[i][0]:
                s_list = s_list[-(shift[i])[1]:] + s_list[:-(shift[i][1])]
            else:
                s_list = s_list[(shift[i][1]):] + s_list[:(shift[i][1])] 
        return ''.join(s_list)