add 14011029 files

Author: poyynt

14011029/MergeSort.java

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+import java.util.Scanner;
+import java.util.ArrayList;
+
+class MergeSort {
+	public static ArrayList<Integer> mergeSort(ArrayList<Integer> a) {
+		int n = a.size();
+		if (n <= 1)
+			return a;
+		ArrayList<Integer> l = new ArrayList<Integer>();
+		ArrayList<Integer> r = new ArrayList<Integer>();
+		for (int i = 0; i < n / 2; i++)
+			l.add(a.get(i));
+		for (int i = n / 2; i < n; i++)
+			r.add(a.get(i));
+		ArrayList<Integer> ls = mergeSort(l);
+		ArrayList<Integer> rs = mergeSort(r);
+		ArrayList<Integer> ans = new ArrayList<Integer>();
+		int i = 0, j = 0;
+		while (ans.size() < n) {
+			if (i < ls.size() && j < rs.size()) {
+				if (ls.get(i) < rs.get(j)) {
+					ans.add(ls.get(i));
+					i++;
+				}
+				else {
+					ans.add(rs.get(j));
+					j++;
+				}
+			}
+			else if (i < ls.size()) {
+				ans.add(ls.get(i));
+				i++;
+			}
+			else if (j < rs.size()) {
+				ans.add(rs.get(j));
+				j++;
+			}
+		}
+		return ans;
+	}
+	public static void main(String[] args) {
+		Scanner stdin = new Scanner(System.in);
+		int n = stdin.nextInt();
+		ArrayList<Integer> input = new ArrayList<Integer>();
+		for (int i = 0; i < n; i++) {
+			int t = stdin.nextInt();
+			input.add(t);
+		}
+		ArrayList<Integer> sorted = mergeSort(input);
+		for (Integer i: sorted)
+			System.out.print(i + " ");
+		System.out.println();
+	}
+}

14011029/Subsets.java

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+import java.util.Scanner;
+import java.util.ArrayList;
+
+class Subsets {
+	public static ArrayList<ArrayList<Integer>> getSubsets(ArrayList<Integer> S) {
+		if (S.size() == 0) {
+			ArrayList<ArrayList<Integer>> ans = new ArrayList<ArrayList<Integer>>();
+			ans.add(new ArrayList<Integer>());
+			return ans;
+		}
+		int x = S.get(0);
+		ArrayList<Integer> T = new ArrayList<Integer>();
+		for (int i = 1; i < S.size(); i++)
+			T.add(S.get(i));
+		ArrayList<ArrayList<Integer>> A = getSubsets(T);
+		ArrayList<ArrayList<Integer>> B = new ArrayList<ArrayList<Integer>>();
+		for (int i = 0; i < A.size(); i++) {
+			ArrayList<Integer> Y = A.get(i);
+			ArrayList<Integer> Z = new ArrayList<Integer>(Y);
+			B.add(Z);
+			Y.add(x);
+			B.add(Y);
+		}
+		return B;
+	}
+	public static void main(String[] args) {
+		Scanner stdin = new Scanner(System.in);
+		int n = stdin.nextInt();
+		ArrayList<Integer> S = new ArrayList<Integer>();
+		for (int i = 0; i < n; i++) {
+			int t = stdin.nextInt();
+			S.add(t);
+		}
+		ArrayList<ArrayList<Integer>> subsets = getSubsets(S);
+		for (ArrayList<Integer> X: subsets) {
+			System.out.print("{");
+			for (Integer i: X)
+				System.out.print(i + ", ");
+			System.out.println("}");
+		}
+	}
+}

14011029/Tiling.java

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+import java.util.Scanner;
+
+class Tiling {
+	public static int f(int n) {
+		if (n == 1) 
+			return 2;
+		if (n == 2)
+			return 7;
+		return f(n - 1) + g(n - 1) + f(n - 2) + g(n - 2);
+	}
+
+	public static int g(int n) {
+		if (n == 0) 
+			return 1;
+		if (n == 1)
+			return 3;
+		return f(n) + g(n - 1);
+	}
+
+	public static void main(String[] args) {
+		Scanner stdin = new Scanner(System.in);
+		int n = stdin.nextInt();
+		System.out.println(f(n));
+	}
+}

14011029/notes.pdf

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+https://quera.org/problemset/305
+https://quera.org/problemset/12912
+https://quera.org/problemset/643
+https://quera.org/problemset/608
+https://quera.org/problemset/605
+https://quera.org/problemset/9722
+https://quera.org/problemset/604