- Difficulty: Medium
- Tags: LeetCode, Medium, Array, Two Pointers, Binary Search, Sorting, leetcode-1498, O(nlogn), O(n)
Problem
You are given an array of integers nums
and an integer target
.
Return the number of non-empty subsequences of nums
such that the sum of the minimum and maximum element on it is less or equal to target
. Since the answer may be too large, return it modulo 109 + 7
.
Example 1:
Input: nums = [3,5,6,7], target = 9 Output: 4 Explanation: There are 4 subsequences that satisfy the condition. [3] -> Min value + max value <= target (3 + 3 <= 9) [3,5] -> (3 + 5 <= 9) [3,5,6] -> (3 + 6 <= 9) [3,6] -> (3 + 6 <= 9)
Example 2:
Input: nums = [3,3,6,8], target = 10 Output: 6 Explanation: There are 6 subsequences that satisfy the condition. (nums can have repeated numbers). [3] , [3] , [3,3], [3,6] , [3,6] , [3,3,6]
Example 3:
Input: nums = [2,3,3,4,6,7], target = 12 Output: 61 Explanation: There are 63 non-empty subsequences, two of them do not satisfy the condition ([6,7], [7]). Number of valid subsequences (63 - 2 = 61).
Constraints:
1 <= nums.length <= 105
1 <= nums[i] <= 106
1 <= target <= 106