Study/260209

problems/SWEA/p10972/Main.java

@@ -0,0 +1,81 @@
+/*
+ * (10972) 다음 순열
+ * https://www.acmicpc.net/problem/10972
+ */
+package boj.p10972;
+
+import java.io.*;
+import java.util.*;
+
+/**
+ * SW Expert Academy - 다음 순열
+ * @author YeJun, Jung
+ *
+ * nextPermutation
+ *   - 오름차순으로 정렬되어 있는 배열을 내림차순으로 변경하는 과정에서 순열을 생성하는 알고리즘
+ *   - 이번 문제에서 말하는 사전순으로 다음에 오는 순열은 nextPermutation이 생성하는 순서와 일치한다.
+ *   - nextPermutation 구현체는 C++의 표준 라이브러리 구현체를 참고했다.
+ *   
+ * 참고자료
+ *   - https://en.cppreference.com/w/cpp/algorithm/next_permutation.html
+ *   - https://charles098.tistory.com/8
+ */
+public class Main {
+	static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
+	static StringTokenizer input;
+
+	// --------------------------------------------------------
+
+	public static void main(String[] args) throws IOException {
+		new Main().run();
+	}
+
+	// --------------------------------------------------------
+
+	int arrLen;
+	int[] arr;
+
+	public void run() throws IOException {
+		arrLen = Integer.parseInt(reader.readLine().trim());
+		arr = new int[arrLen];
+
+		getLine();
+		for (int index = 0; index < arrLen; index++) {
+			arr[index] = Integer.parseInt(input.nextToken());
+		}
+
+		if (nextPermutation(arr)) {
+			for (int index = 0; index < arrLen; index++) {
+				writer.write(arr[index] + " ");
+			}
+			writer.write("\n");
+		} else {
+			writer.write("-1\n");
+		}
+		writer.flush();
+	}
+
+	// --------------------------------------------------------
+
+	private void getLine() throws IOException {
+		input = new StringTokenizer(reader.readLine().trim());
+	}
+
+	private boolean nextPermutation(int[] x) {
+		int n = x.length - 1, a = n, b = n;
+		while (a > 0 && x[a - 1] >= x[a]) a--;
+		if (a == 0) return false;
+		while (x[a - 1] >= x[b]) b--;
+		swap(x, a - 1, b); reverse(x, a, n);
+		return true;
+	}
+
+	private void swap(int[] x, int a, int b) {
+		int t = x[a]; x[a] = x[b]; x[b] = t;
+	}
+
+	private void reverse(int[] x, int a, int b) {
+		while (a < b) swap(x, a++, b--);
+	}
+}

problems/SWEA/p1767/Solution.java

@@ -0,0 +1,201 @@
+/*
+ * (1767) [SW Test 샘플문제] 프로세서 연결하기
+ * https://swexpertacademy.com/main/code/problem/problemDetail.do?contestProbId=AV4suNtaXFEDFAUf&categoryId=AV4suNtaXFEDFAUf&categoryType=CODE&problemTitle=1767&orderBy=FIRST_REG_DATETIME&selectCodeLang=ALL&select-1=&pageSize=10&pageIndex=1
+ */
+package swea.p1767;
+
+import java.io.*;
+import java.util.*;
+
+/**
+ * SW Expert Academy - [SW Test 샘플문제] 프로세서 연결하기
+ * @author YeJun, Jung
+ * 
+ * - DFS, 백트래킹 적용
+ * 	- DFS: 전원 공급이 안되는 코어를 상하좌우 전선 연결 시도
+ * 	- 백트래킹: 전선이 다른 전선 및 코어에 부딪치면 탐색 중단
+ * - 상하좌우 전선 연결시에는 델타 배열을 사용
+ * - DFS 탐색을 위해서 Deque 사용
+ * 	- DFS 탐색 중 값을 저장하기 위해 Context 클래스 사용
+ * - Pos 클래스를 사용해서 좌표를 보관
+ */
+public class Solution {
+	static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
+
+	// --------------------------------------------------------
+
+	public static void main(String[] args) throws IOException {
+		final int testCount = Integer.parseInt(reader.readLine().trim());
+
+		for (int testCase = 1; testCase <= testCount; testCase++) {
+			new Solution(testCase).run();
+		}
+	}
+
+	// --------------------------------------------------------
+
+	final static int[] DIR_X = { 0, -1,  1,  0,  0 };
+	final static int[] DIR_Y = { 0,  0,  0, -1,  1 };
+	final static int DIR_LEN = 5;
+
+	int testCase;
+	int cost;
+	int connectedCores;
+
+	int boardSize;
+	char[][] board;
+
+	List<Pos> corePosList;
+
+	public Solution(int testCase) {
+		this.testCase = testCase;
+	}
+
+	public void run() throws IOException {
+		input();
+		solve();
+		print();
+	}
+
+	private void input() throws IOException {
+		boardSize = Integer.parseInt(reader.readLine().trim());
+		board = new char[boardSize][boardSize];
+
+		corePosList = new ArrayList<>();
+
+		for (int y = 0; y < boardSize; y++) {
+			String line = reader.readLine().trim();
+			for (int x = 0; x < boardSize; x++) {
+				char ch = line.charAt(x * 2);
+				board[y][x] = ch;
+
+				// 가장자리에 있어 이미 전원이 공급되는 코어는 제외한다.
+				if (ch == '1' && !isSidePos(x, y)) corePosList.add(new Pos(x, y));
+			}
+		}
+	}
+
+	private boolean isSidePos(int x, int y) {
+		return x == 0 || x == boardSize - 1 || y == 0 || y == boardSize - 1;
+	}
+
+	private void solve() {
+		cost = Integer.MAX_VALUE;
+		connectedCores = -1;
+
+		// DFS 탐색 시작
+		searchBoard();
+	}
+
+	private void searchBoard() {
+		final int corePosLen = corePosList.size();
+
+		Deque<Context> q = new ArrayDeque<>();
+		q.push(new Context(board.clone(), 0, 0, 0));
+
+		while (!q.isEmpty()) {
+			Context top = q.pop();
+
+			// 기저 조건
+			if (top.coreIndex >= corePosLen) {
+				// 연결된 코어수가 더 많거나 사용한 전선 길이가 작은 경우를 찾는다
+				if (top.connectedCores == connectedCores) {
+					if (top.cost < cost) {
+						cost = top.cost;
+					}
+				} else if (top.connectedCores > connectedCores) {
+					cost = top.cost;
+					connectedCores = top.connectedCores;
+				}
+
+				// 기저조건 도달시 탐색 중단
+				continue;
+			}
+
+			Pos corePos = corePosList.get(top.coreIndex);
+			for (int dir = 0; dir < DIR_LEN; dir++) {
+				Context nextCtx = top.nextCtx();
+
+				// 백트래킹
+				if (nextCtx.drawLine(corePos.x, corePos.y, DIR_X[dir], DIR_Y[dir])) {
+					q.push(nextCtx);
+				}
+			}
+		}
+	}
+
+	private void print() throws IOException {
+		writer.write("#" + testCase);
+		writer.write(" " + cost);
+		writer.write("\n");
+		writer.flush();
+	}
+
+	// --------------------------------------------------------
+
+	private class Context {
+		final int boardSize;
+		char[][] board;
+		int coreIndex;
+		int cost;
+		int connectedCores;
+
+		public Context(char[][] board, int coreIndex, int cost, int connectedCores) {
+			this.boardSize = board.length;
+			this.board = board;
+			this.coreIndex = coreIndex;
+			this.cost = cost;
+			this.connectedCores = connectedCores;
+		}
+
+		public Context nextCtx() {
+			char[][] nextBoard = new char[boardSize][boardSize];
+
+			for (int y = 0; y < boardSize; y++) {
+				nextBoard[y] = board[y].clone();
+			}
+
+			return new Context(nextBoard, coreIndex + 1, cost, connectedCores);
+		}
+
+		public boolean drawLine(int coreX, int coreY, int deltaX, int deltaY) {
+			if (deltaX == 0 && deltaY == 0) return true;
+
+			while (true) {
+				coreX += deltaX;
+				coreY += deltaY;
+
+				if (!isInsideBoard(coreX, coreY)) break;
+				if (board[coreY][coreX] != '0') return false;
+
+				board[coreY][coreX] = '#';
+				cost++;
+			}
+
+			connectedCores++;
+			return true;
+		}
+
+		private boolean isInsideBoard(int x, int y) {
+			if (x < 0 || x >= boardSize || y < 0 || y >= boardSize) {
+				return false;
+			}
+			return true;
+		}
+	}
+
+	// --------------------------------------------------------
+
+	private class Pos {
+		int x;
+		int y;
+
+		public Pos(int x, int y) {
+			this.x = x;
+			this.y = y;
+		}
+	}
+
+	// --------------------------------------------------------
+}