고다혜: [BOJ] 16724 피리 부는 사나이_250211

BOJ/15001-20000번/DH_16724.java

@@ -0,0 +1,85 @@
+import java.io.*;
+import java.util.*;
+
+/*
+ * 피리 부는 사나이
+ */
+
+public class DH_16724 {
+	static int N, M, cnt;
+	static char[][] map;
+	static int[] p;
+	static int[] dr = {-1, 1, 0, 0}, dc = {0, 0, -1, 1};
+
+	public static void main(String[] args) throws Exception {
+		initInput();
+		initParent();
+
+		for(int r = 0; r < N; r++) {
+			for(int c = 0; c < M; c++) {
+
+				int dir = dir(map[r][c]);
+				int nr = r + dr[dir], nc = c + dc[dir];
+
+				int pos = r * M + c;
+				int npos = nr * M + nc;
+
+				if(p[pos] == p[npos]) continue;
+				union(pos, npos);
+			}
+		}
+
+		HashSet<Integer> parentSet = new HashSet<Integer>();
+
+		for(int p: p) parentSet.add(find(p));
+
+		System.out.println(parentSet.size());
+	}
+
+	static void initParent() {
+		for(int r = 0; r < N; r++) {
+			for(int c = 0; c < M; c++) {
+				int pos = r * M + c;
+				p[pos] = pos;
+			}
+		}
+	}
+
+	static void union(int a, int b) {
+		a = find(a);
+		b = find(b);
+
+		if(a != b) p[b] = a;
+	}
+
+	static int find(int a) {
+		return p[a] = p[a] == a ? a : find(p[a]);
+	}
+
+	static boolean check(int r, int c) {
+		return r >= 0 && r < N && c >= 0 && c < M;
+	}
+
+	static void initInput() throws Exception {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+
+		map = new char[N][M];
+		p = new int[N * M];
+
+		for(int r = 0; r < N; r++) {
+			String s = br.readLine();
+			map[r] = s.toCharArray();
+		}
+	}
+
+	static int dir(char c) {
+		if(c == 'U') return 0;
+		if(c == 'D') return 1;
+		if(c == 'L') return 2;
+		else return 3;
+	}
+}

BOJ/15001-20000번/DH_16724WA.java

@@ -0,0 +1,96 @@
+import java.io.*;
+import java.util.*;
+
+/*
+ * 피리 부는 사나이
+ * 스택 오버플로우 발생하는데 통과되는 코드
+ */
+
+public class DH_16724WA {
+	static int N, M, cnt;
+	static char[][] map;
+	static int[][] idx;
+	static HashMap<Integer, Integer> p = new HashMap<Integer, Integer>();
+
+	static int[] dr = {-1, 1, 0, 0}, dc = {0, 0, -1, 1};
+
+	public static void main(String[] args) throws Exception {
+		initInput();
+
+		idx = new int[N][M];
+
+		int cnt = 1;
+
+		for(int r = 0; r < N; r++) {
+			for(int c = 0; c < M; c++) {
+				if(idx[r][c] != 0) continue;
+
+				p.put(cnt, cnt);
+
+				dfs(r, c, cnt);
+				cnt += 1;
+			}
+		}
+
+		HashSet<Integer> parentSet = new HashSet<Integer>();
+		for(int key: p.keySet()) {
+			parentSet.add(find(p.get(key)));
+		}
+		System.out.println(parentSet.size());
+	}
+
+	static void dfs(int r, int c, int cnt) {
+
+		idx[r][c] = cnt;
+
+		int dir = dir(map[r][c]);
+		int nr = r + dr[dir];
+		int nc = c + dc[dir];
+
+		if(idx[nr][nc] != 0) {
+			if(idx[nr][nc] == cnt) return;
+			else union(cnt, idx[nr][nc]);
+		} else dfs(nr, nc, cnt);
+	}
+
+	static void union(int a, int b) {
+		a = find(a);
+		b = find(b);
+
+		if(a != b) p.put(b, a);
+	}
+
+	static int find(int a) {
+
+		if(a == p.get(a)) return a;
+		else {
+			p.put(a, find(p.get(a)));
+			return p.get(a);
+		}
+	}
+
+	static boolean check(int r, int c) {
+		return r >= 0 && r < N && c >= 0 && c < M;
+	}
+	static void initInput() throws Exception {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+
+		map = new char[N][M];
+
+		for(int r = 0; r < N; r++) {
+			String s = br.readLine();
+			map[r] = s.toCharArray();
+		}
+	}
+
+	static int dir(char c) {
+		if(c == 'U') return 0;
+		if(c == 'D') return 1;
+		if(c == 'L') return 2;
+		else return 3;
+	}
+}