Suppose you are given 2 strings which will include digits from 0-9 and the string can be of any length. You need to add those 2 strings as numbers and return the output as string. You need to do this as efficiently as possible. Again emphasizing on the point that the string can be of any length.
Example-1
str1 = "123456"
str2 = "312321"
output = "435777"
Example-2
str1 = "123456"
str2 = "123456"
output = "246912"
Suppose you are give 2 strings, one the input and the other one as the unwant.
You need to find the occurence of the unwant string and remove it from the input. You need to basically remove all the unwant string occurences from the input.
Example-1
input = "daabcbaabcbc", unwant = "abc"
Output: "dab"
Explanation: The following operations are done:
- input = "daabcbaabcbc", remove "abc" starting at index 2, so input = "dabaabcbc".
- input = "dabaabcbc", remove "abc" starting at index 4, input = "dababc".
- input = "dababc", remove "abc" starting at index 3, so input = "dab". Now s has no occurrences of "abc".
Example-2
input = "axxxxyyyyb", unwant = "xy"
Output: "ab"
Explanation: The following operations are done:
- input = "axxxxyyyyb", remove "xy" starting at index 4 so input = "axxxyyyb".
- input = "axxxyyyb", remove "xy" starting at index 3 so input = "axxyyb".
- input = "axxyyb", remove "xy" starting at index 2 so input = "axyb".
- input = "axyb", remove "xy" starting at index 1 so input = "ab".
Now input has no occurrences of "xy".