add: 220327-CN [cpp]

cpp/2203/220327-CN.cpp

@@ -0,0 +1,39 @@
+#include <vector>
+#include <numeric>
+
+/**
+ * 2028. Find Missing Observations
+ * You have observations of n + m 6-sided dice rolls with each face numbered from 1 to 6. n of the observations went missing, and you only have the observations of m rolls. Fortunately, you have also calculated the average value of the n + m rolls.
+ * You are given an integer array rolls of length m where rolls[i] is the value of the ith observation. You are also given the two integers mean and n.
+ * Return an array of length n containing the missing observations such that the average value of the n + m rolls is exactly mean. If there are multiple valid answers, return any of them. If no such array exists, return an empty array.
+ * The average value of a set of k numbers is the sum of the numbers divided by k.
+ * Note that mean is an integer, so the sum of the n + m rolls should be divisible by n + m.
+ */
+
+class Solution {
+public:
+	static std::vector<int> missingRolls(const std::vector<int>& rolls, int mean, int n) {
+		int sum = std::accumulate(rolls.begin(), rolls.end(), 0);
+		int rem = (n + rolls.size()) * mean - sum;
+		if (rem < n || rem > 6 * n)
+			return {};
+		std::vector<int> ret(n, rem / n);
+		rem = rem - rem / n * n;
+		for (int& i : ret) {
+			if (rem <= 0)
+				break;
+			if (rem < 6 - i) {
+				i += rem;
+				break;
+			}
+			rem -= 6 - i;
+			i = 6;
+		}
+		return ret;
+	}
+};
+
+int main() {
+	auto ret = Solution::missingRolls({1, 5, 6}, 3, 4);
+	return 0;
+}

cpp/2203/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220327.cpp)
+ADD_EXECUTABLE(2203 220327-CN.cpp)