14 November 2023
By: ThinkingFunctionally
1877 Minimize Maximum Pair Sum in Array
(defn min-pair-sum [nums]
(let [sorted-nums (sort nums)
n (count sorted-nums)]
(loop [i 0
j (dec n)
m 0]
(if (< i j)
(recur (inc i)
(dec j)
(max m (+ (nth sorted-nums i) (nth sorted-nums j))))
m))))
(def nums [3 5 2 3])
(println (min-pair-sum nums))
Certainly! Let's break down the time and space complexity analysis for the given code snippet:
Time Complexity Analysis:
- Sorting the input vector
numsusing thesortfunction takes O(n log n) time, where n is the length of the vector. - The
countfunction is used to determine the length of the sorted vector, which takes O(1) time. - The loop iterates from the start and end of the sorted vector towards the center. The number of iterations in the loop is approximately n/2, where n is the length of the input vector.
- Inside the loop, the operations of incrementing
i, decrementingj, comparingiandjusing<, and calculating the maximum pair sum usingmaxand addition take constant time O(1). - As a result, the overall time complexity is dominated by the sorting operation, resulting in O(n log n) time complexity.
Space Complexity Analysis:
- The space complexity is determined by the auxiliary space used for sorting the input vector. In this case, the
sorted-numsvector is created, which requires additional space of O(n), where n is the length of the input vector. - The
nvariable holds the length of the sorted vector and requires constant space O(1). - The loop variables
i,j, andmare used to keep track of the loop state and require constant space O(1). - Therefore, the overall space complexity is O(n).
In summary, the time complexity of the min-pair-sum function is O(n log n), and the space complexity is O(n), where n is the length of the input vector nums.