Merge branch 'cpinitiative:master' into master

Author: Sosuke23

content/2_Bronze/Complete_Rec.mdx

@@ -1173,6 +1173,7 @@ appear much less frequently than they once did.
 
     	```cpp
     	vector<int> perm(n);
+    	iota(begin(perm), end(perm), 1);
     	do {
     	} while (next_permutation(begin(perm), end(perm)));
     	```

content/4_Gold/Conclusion.problems.json

@@ -278,6 +278,19 @@
         "site": "AC"
       }
     },
+    {
+      "uniqueId": "cf-2021E2",
+      "name": "Digital Village (Hard Version)",
+      "url": "https://codeforces.com/contest/2021/problem/E2",
+      "source": "CF",
+      "difficulty": "Hard",
+      "isStarred": false,
+      "tags": ["DSU", "DP"],
+      "solutionMetadata": {
+        "kind": "autogen-label-from-site",
+        "site": "CF"
+      }
+    },
     {
       "uniqueId": "cf-1713E",
       "name": "Cross Swapping",

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

solutions/bronze/usaco-965.mdx

@@ -58,7 +58,6 @@ int main() {
 ```
 
 </CPPSection>
-
 <JavaSection>
 
 ```java
@@ -158,10 +157,10 @@ public class Lineup {
 	// CodeSnip{Kattio}
 }
 ```
-</JavaSection>
-
 
+</JavaSection>
 </LanguageSection>
+
 </Spoiler>
 
 ## Implementation
@@ -242,6 +241,90 @@ int main() {
 ```
 
 </CPPSection>
+<JavaSection>
+
+```java
+import java.io.*;
+import java.util.*;
+
+class Pair<T, U> {
+	T first;
+	U second;
+
+	public Pair(T first, U second) {
+		this.first = first;
+		this.second = second;
+	}
+}
+
+public class Lineup {
+	private static final int RESTRICT_LEN = 6;
+	// list of cows, in alphabetical order
+	private static final List<String> COWS = Arrays.asList(
+	    "Beatrice", "Belinda", "Bella", "Bessie", "Betsy", "Blue", "Buttercup", "Sue");
+
+	private static List<List<String>> orderings = new ArrayList<>();
+
+	private static void build(List<String> ordering) {
+		// finished building permutation
+		if (ordering.size() == 8) {
+			orderings.add(new ArrayList<>(ordering));
+			return;
+		}
+
+		for (String cow : COWS) {
+			if (!ordering.contains(cow)) {
+				ordering.add(cow);
+				build(ordering);
+				ordering.remove(ordering.size() - 1);
+			}
+		}
+	}
+
+	// returns index of a cow in an ordering
+	private static int loc(List<String> order, String cow) {
+		return order.indexOf(cow);
+	}
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new FileReader("lineup.in"));
+
+		int n = Integer.parseInt(br.readLine().trim());
+		List<Pair<String, String>> restrictions = new ArrayList<>();
+
+		for (int i = 0; i < n; i++) {
+			String[] words = br.readLine().split(" ");
+			restrictions.add(new Pair<>(words[0], words[words.length - 1]));
+		}
+
+		br.close();
+
+		// build all possible orderings of cows
+		build(new ArrayList<>());
+
+		PrintWriter pw =
+		    new PrintWriter(new BufferedWriter(new FileWriter("lineup.out")));
+		for (List<String> order : orderings) {
+			boolean ok = true;
+			for (Pair<String, String> rule : restrictions) {
+				if (Math.abs(loc(order, rule.first) - loc(order, rule.second)) > 1) {
+					ok = false;
+					break;
+				}
+			}
+
+			if (ok) {
+				for (String cow : order) { pw.println(cow); }
+				break;
+			}
+		}
+
+		pw.close();
+	}
+}
+```
+
+</JavaSection>
 <PySection>
 
 ```py