add PairsOfSongsWithTotalDurationsDivisibleBy60 - Day 8

src/com/concept/scala/leetcode_30days_challenge_December2020/PairsOfSongsWithTotalDurationsDivisibleBy60.scala

@@ -0,0 +1,55 @@
+package com.concept.scala.leetcode_30days_challenge_December2020
+
+/** **
+ * Day 8
+ *
+ * @todo 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 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.
+ * @note 1 <= time.length <= 6 * 104
+ * 1 <= time[i] <= 500
+ * @see https://leetcode.com/explore/challenge/card/december-leetcoding-challenge/570/week-2-december-8th-december-14th/3559/
+ * OR
+ * https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60
+ *
+ *
+ */
+object PairsOfSongsWithTotalDurationsDivisibleBy60 {
+
+ /** *
+ * 34 / 34 test cases passed.
+ * Status: Accepted
+ * Runtime: 580 ms
+ * Memory Usage: 58.5 MB
+ *
+ */
+ def numPairsDivisibleBy60(time: Array[Int]): Int = {
+ val DENOMINATOR = 60
+ var result = 0
+ val remainders = new Array[Int](DENOMINATOR)
+ for (number <- time) {
+ val rem = number % DENOMINATOR
+ result += remainders((DENOMINATOR - rem) % DENOMINATOR)
+ remainders(rem) += 1
+ }
+ result
+ //time.combinations(2).count(_.sum % 60 == 0)
+ }
+
+ def main(args: Array[String]): Unit = {
+ println(numPairsDivisibleBy60(Array(60, 60, 60)))
+ println(numPairsDivisibleBy60(Array(30, 60, 30)))
+ }
+}