Week9 박태환_SWEA 1949 등산로조성 풀이

src/week9/makingTrailSWEA1949/Main.java

@@ -1,4 +1,164 @@
 package week9.makingTrailSWEA1949;
 
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Queue;
+import java.util.StringTokenizer;
+
 public class Main {
+	static class Point {
+		int r, c, chance, dis, map[][];
+		boolean[][] isSelected;
+
+		public Point(int r, int c, int chance, int dis, int map[][], boolean isSelected[][]) {
+			super();
+			this.r = r;
+			this.c = c;
+			this.chance = chance;
+			this.dis = dis;
+			this.map = map;
+			this.isSelected = isSelected;
+		}
+
+		@Override
+		public String toString() {
+			return "Point [r=" + r + ", c=" + c + " chance=" + chance + " dis=" + dis + "]";
+		}
+	}
+
+	static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+
+	static int N, K;
+	static int[][] map;
+
+	static ArrayList<Point> highList;
+
+	public static void main(String[] args) throws IOException {
+		int T = Integer.parseInt(in.readLine());
+		StringBuilder sb = new StringBuilder();
+
+		for (int tc = 1; tc <= T; tc++) {
+			StringTokenizer st = new StringTokenizer(in.readLine());
+
+			N = Integer.parseInt(st.nextToken());
+			K = Integer.parseInt(st.nextToken());
+
+			map = new int[N][N];
+			highList = new ArrayList<>();
+
+			int high = 0;
+			for (int r = 0; r < N; r++) {
+				st = new StringTokenizer(in.readLine());
+				for (int c = 0; c < N; c++) {
+					map[r][c] = Integer.parseInt(st.nextToken());
+					high = Math.max(map[r][c], high);
+				}
+			}
+
+			boolean[][] isSelected = new boolean[N][N];
+
+			for (int r = 0; r < N; r++) {
+				for (int c = 0; c < N; c++) {
+					if (map[r][c] == high) {
+						//한 곳 만 깍을 수 있기 때문에 chance 1로 줌.
+						isSelected[r][c] = true;
+						highList.add(new Point(r, c, 1, 1, map, isSelected));
+						isSelected = new boolean[N][N];
+
+					}
+				}
+			}
+
+			int result = -1;
+			for (int i = 0; i < highList.size(); i++) {
+				result = Math.max(result, bfs(highList.get(i)));
+			}
+
+			sb.append("#" + tc + " " + result + "\n");
+		}
+		System.out.println(sb);
+	}
+
+	private static int bfs(Point start) {
+		final int[][] dArr = new int[][] { { -1, 0 }, { 0, 1 }, { 1, 0 }, { 0, -1 } };
+		Queue<Point> bfsQ = new ArrayDeque<>();
+
+		bfsQ.add(start);
+		int dis = start.dis;
+
+		while (!bfsQ.isEmpty()) {
+			Point point = bfsQ.poll();
+
+			int r = point.r;
+			int c = point.c;
+			int chance = point.chance;
+			dis = point.dis;
+
+			boolean[][] isSelected = copy(point.isSelected);
+			int[][] pollMap = copy(point.map);
+			int curHigh = pollMap[r][c];
+
+			for (int i = 0; i < 4; i++) {
+				int dr = r + dArr[i][0];
+				int dc = c + dArr[i][1];
+
+				// 범위 내 들어오는지 확인
+				if (isIn(dr, dc)) {
+					//다음 위치가 나보다 클 때 높이를 깍아서 들어갈 수 있는 곳인지 확인
+					if (pollMap[dr][dc] >= curHigh && pollMap[dr][dc] - K < curHigh && !isSelected[dr][dc]) {
+						// 깍을 수 있는 기회가 있다.
+						if (chance == 1) {
+							// 다음칸이 높아서 올라갈 수 없을 때, 깍아서 갈 수 있는 곳인지 확인
+							int[][] nextMap = new int[N][N];
+							nextMap = copy(pollMap);
+							nextMap[dr][dc] = curHigh - 1;
+
+							boolean[][] nextIsSelected = new boolean[N][N];
+							nextIsSelected = copy(isSelected);
+							nextIsSelected[dr][dc] = true;
+							bfsQ.offer(new Point(dr, dc, 0, dis + 1, nextMap, nextIsSelected));
+						}
+					}
+					// 깍을 수 있는 기회가 없다 -> K만큼 깍을 필요 없음.
+					else {
+						if (pollMap[dr][dc] < curHigh && !isSelected[dr][dc]) {
+							boolean[][] nextIsSelected = new boolean[N][N];
+							nextIsSelected = copy(isSelected);
+							nextIsSelected[dr][dc] = true;
+							bfsQ.offer(new Point(dr, dc, chance, dis + 1, pollMap, nextIsSelected));
+						}
+					}
+				}
+			}
+		}
+
+		return dis;
+	}
+
+	private static int[][] copy(int[][] map) {
+		int[][] temp = new int[N][N];
+		for (int i = 0; i < N; i++) {
+			for (int j = 0; j < N; j++) {
+				temp[i][j] = map[i][j];
+			}
+		}
+		return temp;
+	}
+
+	private static boolean[][] copy(boolean[][] map) {
+		boolean[][] temp = new boolean[N][N];
+		for (int i = 0; i < N; i++) {
+			for (int j = 0; j < N; j++) {
+				temp[i][j] = map[i][j];
+			}
+		}
+		return temp;
+	}
+
+	private static boolean isIn(int dr, int dc) {
+		return dr >= 0 && dc >= 0 && dr < N && dc < N;
+	}
 }