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[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

# @lc code=start
using LeetCode

function num_pairs_divisible_by60(time::Vector{Int})
    res = 0
    dct = fill(0, 60)
    for t in time
        (t % 60 == 0) ? (dct[60] += 1) : (dct[t % 60] += 1)
    end
    for i in 1:29
        res += dct[i] * dct[60 - i]
    end
    res += sum(1:(dct[30] - 1)) + sum(1:(dct[60] - 1))
    return res
end
# @lc code=end

num_pairs_divisible_by60 (generic function with 1 method)

This page was generated using DemoCards.jl and Literate.jl.