Skip to content

1010. Pairs of Songs With Total Durations Divisible by 60

Difficulty Topics

Description

You are given a list of songs where the ith song has a duration of time[i] seconds.

Return the number of pairs of songs for which their total duration in seconds is divisible by 60. Formally, we want the number of indices i, j such that i < j with (time[i] + time[j]) % 60 == 0.

 

Example 1:

Input: time = [30,20,150,100,40]
Output: 3
Explanation: Three pairs have a total duration divisible by 60:
(time[0] = 30, time[2] = 150): total duration 180
(time[1] = 20, time[3] = 100): total duration 120
(time[1] = 20, time[4] = 40): total duration 60

Example 2:

Input: time = [60,60,60]
Output: 3
Explanation: All three pairs have a total duration of 120, which is divisible by 60.

 

Constraints:

  • 1 <= time.length <= 6 * 104
  • 1 <= time[i] <= 500

Solution

pairs-of-songs-with-total-durations-divisible-by-60.py
class Solution:
    def numPairsDivisibleBy60(self, time: List[int]) -> int:
        s = res = 0
        mp = Counter()

        for x in time:
            target = (60 - x) % 60

            res += mp[target]

            mp[x % 60] += 1

        return res