# 1010 Pairs of Songs With Total Durations Divisible by 60

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 = 30, time = 150): total duration 180
(time = 20, time = 100): total duration 120
(time = 20, time = 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`
 `````` 1 2 3 4 5 6 7 8 9 10 11 `````` ``````class Solution: def numPairsDivisibleBy60(self, time: List[int]) -> int: d = collections.defaultdict(int) res = 0 for t in time: if t % 60 == 0: res += d else: res += d[60 - t % 60] d[t % 60] += 1 return res``````