_1010.java

packagecom.fishercoder.solutions.secondthousand;

importjava.util.HashMap;
importjava.util.Map;

publicclass_1010 {
publicstaticclassSolution1 {
/*
 * Credit: https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/discuss/256726/Java-O(n)-code-w-comment-similar-to-Two-Sum
 * <p>
 * Think of Problem 1: Two Sum
 * Assume target is 60, each item in time % 60.
 * Then this problem becomes very similar to Problem 1.
 */
publicintnumPairsDivisibleBy60(int[] time) {
intresult = 0;
Map<Integer, Integer> map = newHashMap<>();
for (intt : time) {
intd = (60 - t % 60) % 60;
if (map.containsKey(d)) {
result += map.get(d);
 }
map.put(t % 60, map.getOrDefault(t % 60, 0) + 1);
 }
returnresult;
 }
 }

publicstaticclassSolution2 {
/*
 * credit: https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/solution/
 */
publicintnumPairsDivisibleBy60(int[] time) {
int[] remainders = newint[60];
intans = 0;
for (intt : time) {
if (t % 60 == 0) {
ans += remainders[0];
 } else {
ans += remainders[60 - t % 60];
 }
remainders[t % 60]++;
 }
returnans;
 }
 }
}