Problem Statement

You are given a list of positive integer times, where times[i] represents the duration of i^th song in seconds.

Return the number of unique song pairs for which their total duration in seconds is multiple of 60. In other words, find the number of indices i, j such that i < j with (times[i] + times[j]) % 60 == 0.

Examples

Example 1:

• Input: times = [30, 20, 150, 100, 40, 110]
• Expected Output: 3
• Justification: The pairs of songs that can form a total duration divisible by 60 are (30, 150), (20, 100), and (20, 40). Each of these pairs sums up to a multiple of 60, hence the expected output is 3.

Example 2:

• Input: times = [120, 180, 60]
• Expected Output: 3
• Justification: The sum of (120, 180), (120, 60), and (180, 60) are divisible by 60. So, the expected output is 3.

Example 3:

• Input: times = [15, 225, 90, 60]
• Expected Output: 1
• Justification: The only pair of songs that can form a total duration divisible by 60 is (15, 225).

Try it yourself

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