- Difficulty: Medium
- Tags: LeetCode, Medium, Array, Hash Table, Prefix Sum, leetcode-2121, O(n)
Problem
You are given a 0-indexed array of n
integers arr
.
The interval between two elements in arr
is defined as the absolute difference between their indices. More formally, the interval between arr[i]
and arr[j]
is |i - j|
.
Return an array intervals
of length n
where intervals[i]
is the sum of intervals between arr[i]
and each element in arr
with the same value as arr[i]
.
Note: |x|
is the absolute value of x
.
Example 1:
Input: arr = [2,1,3,1,2,3,3] Output: [4,2,7,2,4,4,5] Explanation: - Index 0: Another 2 is found at index 4. |0 - 4| = 4 - Index 1: Another 1 is found at index 3. |1 - 3| = 2 - Index 2: Two more 3s are found at indices 5 and 6. |2 - 5| + |2 - 6| = 7 - Index 3: Another 1 is found at index 1. |3 - 1| = 2 - Index 4: Another 2 is found at index 0. |4 - 0| = 4 - Index 5: Two more 3s are found at indices 2 and 6. |5 - 2| + |5 - 6| = 4 - Index 6: Two more 3s are found at indices 2 and 5. |6 - 2| + |6 - 5| = 5
Example 2:
Input: arr = [10,5,10,10] Output: [5,0,3,4] Explanation: - Index 0: Two more 10s are found at indices 2 and 3. |0 - 2| + |0 - 3| = 5 - Index 1: There is only one 5 in the array, so its sum of intervals to identical elements is 0. - Index 2: Two more 10s are found at indices 0 and 3. |2 - 0| + |2 - 3| = 3 - Index 3: Two more 10s are found at indices 0 and 2. |3 - 0| + |3 - 2| = 4
Constraints:
n == arr.length
1 <= n <= 105
1 <= arr[i] <= 105