add: 230507-CN

cpp/2305/LC230507CN.cpp

@@ -0,0 +1,22 @@
+#include <vector>
+
+/**
+ * 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.
+ */
+
+class LC230507CN {
+public:
+	static int numPairsDivisibleBy60(const std::vector<int>&) noexcept;
+};
+
+int LC230507CN::numPairsDivisibleBy60(const std::vector<int>& time) noexcept {
+	int cnt[60]{}, ret = 0;
+	for (int i : time) {
+		ret += cnt[(60 - i % 60) % 60];
+		++cnt[i % 60];
+	}
+	return ret;
+}