readme.md

Intuition

The function occurrencesOfElement is designed to handle queries regarding the positions of occurrences of a specific element x in an array nums. The function first determines all indices where x appears in nums. Then, it processes a series of queries, each asking for the position of the x occurrence based on its order (e.g., the 1st occurrence, the 2nd occurrence). If a query requests a position beyond the number of times x appears, the function returns -1.

Approach

1. Identify Indices of x:
   • Traverse the array nums and record the indices where the value equals x.
   • Store these indices in a list indexesOfX.
2. Process Queries:
   • For each value in queries, interpret the value as the order of the occurrence of x desired.
   • If the order specified by a query exceeds the number of recorded occurrences (length of indexesOfX), return -1 indicating the query is out of bounds.
   • Otherwise, return the index from indexesOfX that corresponds to the order specified by the query (considering that queries are 1-based).
3. Return Results: Compile the results of each query into an array answer and return this array.

Complexity

• Time complexity: The overall time complexity is $O(n+q)$, where $n$ is the length of the nums array and $q$ is is the number of queries.

• Space complexity: The total space complexity is $O(m+q)$ where $m$ is the number of times x appears in nums and $q$ the length of the answer array.

Code