Merge pull request #5141 from letsbegincode/add-java-solution

Add Java Solution for USACO Problem 1276 - Air Conditioning II

solutions/bronze/usaco-1276.mdx

@@ -122,6 +122,115 @@ int main() {
 ```
 
 </CPPSection>
+<JavaSection>
+
+```java
+import java.io.*;
+import java.util.*;
+
+public class AirConditioningII {
+	static int N, M;
+	// {s, t, c}
+	static List<int[]> cows = new ArrayList<>();
+	// {a, b, p, m}
+	static List<int[]> airConditioners = new ArrayList<>();
+	// uses[i] == true: the i-th air conditioner is used
+	static boolean[] uses;
+	// the minimum amount of money needed to keep all cows comfortable
+	static int minCost = Integer.MAX_VALUE;
+
+	/**
+	 * Based on 'uses', determine if the current subset of air conditioners suffices
+	 * the constraints, and if so, update the minimum cost
+	 */
+	static void update() {
+		boolean isFeasible = true;
+
+		// iterate through all positions to check if the current subset is feasible
+		for (int i = 1; i <= 100; i++) {
+			// iterate through air conditioners to find the current cooling units
+			int cooling = 0;
+			for (int j = 0; j < M; j++) {
+				if (!uses[j]) continue;
+				int[] ac = airConditioners.get(j);
+				int a = ac[0], b = ac[1], p = ac[2];
+				if (a <= i && i <= b) cooling += p;
+			}
+
+			// iterate through cows to find the current cow
+			int cowRequirement = 0;
+			for (int j = 0; j < N; j++) {
+				int[] cow = cows.get(j);
+				int s = cow[0], t = cow[1], c = cow[2];
+				if (s <= i && i <= t) {
+					cowRequirement = c;
+					break;
+				}
+			}
+
+			// For each position, the requirement of the cow must be met
+			if (cooling < cowRequirement) {
+				isFeasible = false;
+				break;
+			}
+		}
+
+		if (isFeasible) {
+			int cost = 0;
+			for (int i = 0; i < M; i++) {
+				if (uses[i]) cost += airConditioners.get(i)[3];
+			}
+			minCost = Math.min(minCost, cost);
+		}
+	}
+
+	/**
+	 * Expand the subset, represented by 'uses', by choosing to (not) use the i-th
+	 * air conditioner
+	 */
+	static void search(int i) {
+		if (i == M) {
+			update();
+		} else {
+			uses[i] = false;
+			search(i + 1);
+			uses[i] = true;
+			search(i + 1);
+		}
+	}
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+
+		for (int i = 0; i < N; i++) {
+			st = new StringTokenizer(br.readLine());
+			int s = Integer.parseInt(st.nextToken());
+			int t = Integer.parseInt(st.nextToken());
+			int c = Integer.parseInt(st.nextToken());
+			cows.add(new int[] {s, t, c});
+		}
+
+		for (int i = 0; i < M; i++) {
+			st = new StringTokenizer(br.readLine());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			int p = Integer.parseInt(st.nextToken());
+			int m = Integer.parseInt(st.nextToken());
+			airConditioners.add(new int[] {a, b, p, m});
+		}
+
+		uses = new boolean[M];
+		search(0);
+
+		System.out.println(minCost);
+	}
+}
+```
+
+</JavaSection>
 <PySection>
 
 ```py