Problem
Leaderboard
🎁 September Giveaway
This September, you have the opportunity to hone your skills and win the Macbook Air, Sony WH-1000XM4 headphones, $50 gift card and much more.
🎮 How to Play
Complete Educative’s daily coding challenge all month.
Choose your preferred programming language before you start, you can switch it anytime, even mid-problem.
Be mindful of your attempts, you only get a limited number, so make each one count.
Keep your streak alive, the longer it runs, the more raffle entry tickets you rack up.
Earn tickets and increase your chances of winning the draw.
🎟️ How to earn Tickets
ActionTickets Earned
Complete Daily Challenge
+1
10-Day Streak
+10
20-Day Streak
+20
30-Day Streak
+30
LinkedIn post with #30DaysofCode Everyday (and tag Educative)
+2 per post
Most-Liked Post Overall
+20
Top of Leaderboard
+50
Leaderboard: 2nd place
+30
Leaderboard: 3rd place
+20

Problem: Reverse Pairs

Statement

You are given an integer array, nums. Your task is to count how many reverse pairs exist in the array and return the total number of such pairs.

A reverse pair is defined as a pair of indexes (i,j)(i, j) such that:

  • 0≤i<j<0 \leq i \lt j \lt nums.length, and

  • nums[i] >2×\gt 2 \times nums[j].

Constraints:

  • 1≤1 \leq nums.length ≤5×104\leq 5 \times 10^4

  • −231≤-2^{31} \leq nums[i] ≤231−1\leq 2^{31} - 1

Problem
Leaderboard
🎁 September Giveaway
This September, you have the opportunity to hone your skills and win the Macbook Air, Sony WH-1000XM4 headphones, $50 gift card and much more.
🎮 How to Play
Complete Educative’s daily coding challenge all month.
Choose your preferred programming language before you start, you can switch it anytime, even mid-problem.
Be mindful of your attempts, you only get a limited number, so make each one count.
Keep your streak alive, the longer it runs, the more raffle entry tickets you rack up.
Earn tickets and increase your chances of winning the draw.
🎟️ How to earn Tickets
ActionTickets Earned
Complete Daily Challenge
+1
10-Day Streak
+10
20-Day Streak
+20
30-Day Streak
+30
LinkedIn post with #30DaysofCode Everyday (and tag Educative)
+2 per post
Most-Liked Post Overall
+20
Top of Leaderboard
+50
Leaderboard: 2nd place
+30
Leaderboard: 3rd place
+20

Problem: Reverse Pairs

Statement

You are given an integer array, nums. Your task is to count how many reverse pairs exist in the array and return the total number of such pairs.

A reverse pair is defined as a pair of indexes (i,j)(i, j) such that:

  • 0≤i<j<0 \leq i \lt j \lt nums.length, and

  • nums[i] >2×\gt 2 \times nums[j].

Constraints:

  • 1≤1 \leq nums.length ≤5×104\leq 5 \times 10^4

  • −231≤-2^{31} \leq nums[i] ≤231−1\leq 2^{31} - 1