add: 220331 [cpp]

cpp/2203/220331.cpp

@@ -0,0 +1,62 @@
+#include <vector>
+#include <iostream>
+
+/**
+ * 410. Split Array Largest Sum
+ * Given an array nums which consists of non-negative integers and an integer m, you can split the array into m non-empty continuous subarrays.
+ * Write an algorithm to minimize the largest sum among these m subarrays.
+ */
+
+class Solution {
+private:
+	// dp[remaining][startPoint]
+	int dp[51][1002]{};
+	int prefixSum[1002]{};
+	int n = -1;
+	const std::vector<int>* num = nullptr;
+
+	// [remaining] segments to split,
+	// from [startPoint] (inclusive) to the end.
+	int d(int remaining, int startPoint) {
+		if (dp[remaining][startPoint])
+			return dp[remaining][startPoint];
+		if (remaining <= 1)
+			return dp[1][startPoint] = prefixSum[n - 1] - (startPoint ? prefixSum[startPoint - 1] : 0);
+		// We should make sure that we will never
+		// let remaining < n - startPoint.
+		// nextRemaining <- remaining - 1;
+		// from startPoint + 1, while i + nextRemaining < n;
+		int currentSum = num->at(startPoint), ret = 0x7FFFFFFF;
+		for (int i = 1 + startPoint; i + remaining - 1 <= n; ++i) {
+			ret = std::min(ret, std::max(currentSum, d(remaining - 1, i)));
+			currentSum += num->at(i);
+		}
+		return dp[remaining][startPoint] = ret;
+	}
+
+public:
+	int splitArray(const std::vector<int>& nums, int m) {
+		std::vector<int> processed;
+		processed.reserve(nums.size() / 2);
+		for (int i : nums)
+			if (i)
+				processed.push_back(i);
+		n = processed.size();
+		if (!n)
+			return 0;
+		num = &processed;
+		m = std::min(m, n);
+		prefixSum[0] = processed[0];
+		for (int i = 1; i < n; ++i)
+			prefixSum[i] = prefixSum[i - 1] + processed[i];
+		return d(m, 0);
+	}
+};
+
+int main() {
+	Solution s;
+	std::cout << s.splitArray({7,2,5,10,8}, 2);
+	// std::cout << s.splitArray({1,2,3,4,5}, 2);
+	// std::cout << s.splitArray({1,4,4}, 3);
+	return 0;
+}

cpp/2203/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220331-CN.cpp)
+ADD_EXECUTABLE(2203 220331.cpp)