Study/260220

problems/SWEA/p1227/Solution.java

@@ -0,0 +1,134 @@
+/*
+ * (1227) [S/W 문제해결 기본] 7일차 - 미로2
+ * https://swexpertacademy.com/main/code/problem/problemDetail.do?contestProbId=AV14wL9KAGkCFAYD&categoryId=AV14wL9KAGkCFAYD&categoryType=CODE&problemTitle=1227&orderBy=FIRST_REG_DATETIME&selectCodeLang=ALL&select-1=&pageSize=10&pageIndex=1
+ */
+
+import java.io.*;
+import java.util.*;
+
+/**
+ * SW Expert Academy - [S/W 문제해결 기본] 7일차 - 미로2
+ * @author YeJun, Jung
+ * 
+ * [분석]
+ *   - 100x100 미로와, 출발지, 도착지가 주어졌을때 탈출가능 여부를 파악해야 한다.
+ *   - 미로에는 벽, 길 두가지가 있으며 길로만 다닐 수 있다.
+ * 
+ * [전략]
+ *   - 미로의 출발지에서 DFS를 시작한다.
+ *   - 상하좌우로 이동하면서 목적지에 도달하거나, 모든 장소를 방문할때가지 반복한다.
+ *   - 목적지를 찾았다면 '1' 아니면 '0'을 화면에 출력한다.
+ */
+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 = 10;
+
+    for (int testCase = 1; testCase <= testCount; testCase++) {
+      reader.readLine(); // 테스트케이스 입력
+
+      new Solution(testCase).run();
+    }
+  }
+
+  // ----------------------------------------------------------
+
+  static final int BOARD_SIZE = 100;
+  static final char ROAD = '0';
+  static final char WALL = '1';
+  static final char START = '2';
+  static final char GOAL = '3';
+
+  static final int DIR_LEN = 4;
+  static final int[] DIR_X = {  0,  0, -1,  1 };
+  static final int[] DIR_Y = { -1,  1,  0,  0 };
+
+  static char[][] board = new char[BOARD_SIZE][BOARD_SIZE];
+
+  int testCase;
+  int answer;
+  Pos start;
+  boolean[][] visited;
+
+  public Solution(int testCase) {
+    this.testCase = testCase;
+  }
+
+  public void run() throws IOException {
+    input();
+    solve();
+    print();
+  }
+
+  private void input() throws IOException {
+    char[] input;
+    for (int y = 0; y < BOARD_SIZE; y++) {
+      input = reader.readLine().trim().toCharArray();
+
+      for (int x = 0; x < BOARD_SIZE; x++) {
+        board[y][x] = input[x];
+
+        if (board[y][x] == START) {
+          start = new Pos(x, y);
+        }
+      }
+    }
+  }
+
+  private void solve() {
+    visited = new boolean[BOARD_SIZE][BOARD_SIZE];
+    visited[start.y][start.x] = true;
+
+    answer = dfs(start.x, start.y) ? 1 : 0;
+  }
+
+  private boolean dfs(int x, int y) {
+    if (board[y][x] == GOAL) return true;
+
+    for (int dir = 0; dir < DIR_LEN; dir++) {
+      int nx = x + DIR_X[dir];
+      int ny = y + DIR_Y[dir];
+
+      if (!isInsideBoard(nx, ny) ||
+          board[ny][nx] == WALL ||
+          visited[ny][nx]
+      ) {
+        continue;
+      }
+
+      visited[ny][nx] = true;
+      if (dfs(nx, ny)) return true;
+    }
+
+    return false;
+  }
+
+  private boolean isInsideBoard(int x, int y) {
+    return x >= 0 && x < BOARD_SIZE && y >= 0 && y < BOARD_SIZE;
+  }
+
+  private void print() throws IOException {
+    writer.write("#" + testCase);
+    writer.write(" " + answer);
+    writer.write("\n");
+    writer.flush();
+  }
+
+  // ----------------------------------------------------------
+
+  private static class Pos {
+    int x;
+    int y;
+
+    public Pos(int x, int y) {
+      this.x = x;
+      this.y = y;
+    }
+  }
+
+  // ----------------------------------------------------------
+}

problems/SWEA/p1267/Solution.java

@@ -0,0 +1,118 @@
+/*
+ * (1267) [S/W 문제해결 응용] 10일차 - 작업순서
+ * https://swexpertacademy.com/main/code/problem/problemDetail.do?contestProbId=AV18TrIqIwUCFAZN&categoryId=AV18TrIqIwUCFAZN&categoryType=CODE&problemTitle=1267&orderBy=FIRST_REG_DATETIME&selectCodeLang=ALL&select-1=&pageSize=10&pageIndex=1
+ */
+
+import java.io.*;
+import java.util.*;
+
+/**
+ * SW Expert Academy - 1267. [S/W 문제해결 응용] 10일차 - 작업순서
+ * @author YeJun, Jung
+ * 
+ * [분석]
+ *   - 각 작업에는 선행작업이 있을 수 있다.
+ *   - 간선이 없는 노드가 있을 수 있다.(즉 선행작업이 없는 노드가 존재할 수 있음)
+ * 
+ * [전략]
+ *   - 위상정렬을 사용해서 선행작업이 먼저 수행되도록 순서를 만든다.
+ *   - 선행작업이 없는 노드의 작업 순서는 중요하지 않다.
+ */
+public class Solution {
+  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 {
+    final int testCount = 10;
+
+    for (int testCase = 1; testCase <= testCount; testCase++) {
+      new Solution(testCase).run();
+    }
+  }
+
+  // ----------------------------------------------------------
+
+  int testCase;
+  int[] workOrder;
+
+  int nodeLen;
+  int edgeLen;
+  List<List<Integer>> graph;
+  int[] inorder;
+
+  public Solution(int testCase) {
+    this.testCase = testCase;
+  }
+
+  public void run() throws IOException {
+    input();
+    solve();
+    print();
+  }
+
+  private void input() throws IOException {
+    getLine();
+    nodeLen = Integer.parseInt(input.nextToken());
+    edgeLen = Integer.parseInt(input.nextToken());
+
+    graph = new ArrayList<>(nodeLen + 1);
+    for (int node = 0; node <= nodeLen; node++) {
+      graph.add(new ArrayList<>());
+    }
+
+    int nodeA, nodeB;
+    inorder = new int[nodeLen + 1];
+    getLine();
+    while (input.hasMoreTokens()) {
+      nodeA = Integer.parseInt(input.nextToken());
+      nodeB = Integer.parseInt(input.nextToken());
+
+      graph.get(nodeA).add(nodeB);
+      inorder[nodeB]++;
+    }
+  }
+
+  private void solve() {
+    workOrder = new int[nodeLen];
+
+    topologicalSort();
+  }
+
+  private void topologicalSort() {
+    int size = 0;
+    Queue<Integer> q = new ArrayDeque<>();
+
+    for (int node = 1; node <= nodeLen; node++) {
+      if (inorder[node] == 0) q.offer(node);
+    }
+
+    while (!q.isEmpty()) {
+      int peek = q.poll();
+      workOrder[size++] = peek;
+
+      for (int child : graph.get(peek)) {
+        if (--inorder[child] == 0) q.offer(child);
+      }
+    }
+  }
+
+  private void print() throws IOException {
+    writer.write("#" + testCase + " ");
+
+    for (int node : workOrder) {
+      writer.write(node + " ");
+    }
+
+    writer.write("\n");
+    writer.flush();
+  }
+
+  // ----------------------------------------------------------
+
+  private static void getLine() throws IOException {
+    input = new StringTokenizer(reader.readLine().trim());
+  }
+}