August 2023
Description Template:
Level: New Grad
Education: Bachelors
Years of Experience: 2
Questions Asked:
- Valid Perentheses
Given a string s
containing just the characters '('
, ')'
, '{'
, '}'
, '['
and ']'
, determine if the input string is valid.
An input string is valid if:
- Open brackets must be closed by the same type of brackets.
- Open brackets must be closed in the correct order.
- Every close bracket has a corresponding open bracket of the same type.
Example 1:
Input: s = “()”
Output: true
Example 2:
Input: s = “(){}”
Output: true
Example 3:
Input: s = “(]”
Output: false
Example 4:
Input: s = “()”
Output: true
- Find and Replace in string
You are given a 0-indexed string s
that you must perform k
replacement operations on. The replacement operations are given as three 0-indexed parallel arrays, indices
, sources
, and targets
, all of length k
.
To complete the ith
replacement operation:
- Check if the substring
sources[i]
occurs at indexindices[i]
in the original strings
. - If it does not occur, do nothing.
- Otherwise if it does occur, replace that substring with
targets[i]
.
For example, if s = "abcd"
, indices[i] = 0
, sources[i] = "ab"
, and targets[i] = "eee"
, then the result of this replacement will be "eeecd"
.
All replacement operations must occur simultaneously, meaning the replacement operations should not affect the indexing of each other. The testcases will be generated such that the replacements will not overlap.
- For example, a testcase with
s = "abc"
,indices = [0, 1]
, andsources = ["ab","bc"]
will not be generated because the"ab"
and"bc"
replacements overlap.
Return the resulting string after performing all replacement operations on s
.
A substring is a contiguous sequence of characters in a string.