Complete q47_young_shark(청소년상어)

bongf/java/src/ch19_samsung/Q47_YoungShark.java

@@ -0,0 +1,116 @@
+package ch19_samsung;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+//https://www.acmicpc.net/problem/19236
+public class Q47_YoungShark {
+    public static int[] dx = {-1, -1, 0, 1, 1, 1, 0, -1};
+    public static int[] dy = {0, -1, -1, -1, 0, 1, 1, 1};
+    public static int result = 0;
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        Node[][] graph = new Node[4][4];
+        for (int i = 0; i < 4; i++) {
+            String[] input = sc.nextLine().split(" ");
+            for (int j = 0; j < 4; j++) {
+                graph[i][j] = new Node(Integer.parseInt(input[j * 2]), Integer.parseInt(input[j * 2 + 1]) - 1);
+            }
+        }
+        dfs(graph, 0, 0, 0);
+        System.out.println(result);
+    }
+
+    public static int turnLeft(int d) {
+        return (d + 1) % 8;
+    }
+
+    public static int[] findFish(Node[][] graph, int fishNum) {
+        for (int i = 0; i < 4; i++) {
+            for (int j = 0; j < 4; j++) {
+                if (graph[i][j].fishNum == fishNum) {
+                    return new int[]{i, j};
+                }
+            }
+        }
+        return null;
+    }
+
+    public static Node[][] moveFish(Node[][] graph, int sh_x, int sh_y) {
+        for (int i = 0; i < 17; i++) {
+            int[] position = findFish(graph, i);
+            if (position != null) {
+                int x = position[0];
+                int y = position[1];
+                int d = graph[x][y].d;
+                for (int j = 0; j < 8; j++) {
+                    int nx = x + dx[d];
+                    int ny = y + dy[d];
+                    if (0 <= nx && nx < 4 && 0 <= ny && ny < 4) {
+                        if (!(nx == sh_x && ny == sh_y)) {
+                            graph[x][y].d = d;
+                            Node temp = graph[nx][ny];
+                            graph[nx][ny] = graph[x][y];
+                            graph[x][y] = temp;
+                            break;
+                        }
+                    }
+                    d = turnLeft(d);
+                }
+            }
+        }
+        return graph;
+    }
+
+    public static List<int[]> possiblePositions(Node[][] graph, int sh_x, int sh_y) {
+        List<int[]> positions = new ArrayList<>();
+        int d = graph[sh_x][sh_y].d;
+        for (int i = 0; i < 4; i++) {
+            sh_x += dx[d];
+            sh_y += dy[d];
+            if (0 <= sh_x && sh_x < 4 && 0 <= sh_y && sh_y < 4) {
+                if (graph[sh_x][sh_y].fishNum != -1) {
+                    positions.add(new int[]{sh_x, sh_y});
+                }
+            }
+        }
+        return positions;
+    }
+
+    public static void dfs(Node[][] graph, int sh_x, int sh_y, int ate) {
+        ate += graph[sh_x][sh_y].fishNum;
+        graph = copyGraph(graph);
+        graph[sh_x][sh_y].fishNum = -1;
+        Node[][] new_graph = moveFish(graph, sh_x, sh_y);
+        List<int[]> positions = possiblePositions(new_graph, sh_x, sh_y);
+        if (positions.size() == 0) {
+            result = Math.max(ate, result);
+            return;
+        }
+        for (int[] position : positions) {
+            dfs(new_graph, position[0], position[1], ate);
+        }
+    }
+
+    public static Node[][] copyGraph(Node[][] graph) {
+        Node[][] newGraph = new Node[4][4];
+        for (int i = 0; i < 4; i++) {
+            for (int j = 0; j < 4; j++) {
+                newGraph[i][j] = new Node(graph[i][j].fishNum, graph[i][j].d);
+            }
+        }
+        return newGraph;
+    }
+}
+
+class Node {
+    int fishNum;
+    int d;
+
+    public Node(int fishNum, int d) {
+        this.fishNum = fishNum;
+        this.d = d;
+    }
+}

bongf/python/ch19_samaung/q47_young_shark.py

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+## https://www.acmicpc.net/problem/19236
+import copy
+
+def solution():
+    graph = [[] for _ in range(4)]
+    fishes = [() for _ in range(17)]
+    for i in range(4):
+        input_list = list(map(int, input().split()))
+        for j in range(0, 7, 2) :
+            ## 해당 위치에 들어갈 숫자, 방향
+            graph[i].append((input_list[j], input_list[j+1]-1))
+            ## 인덱스를 물고기 번호로 갖는 물고기의 위치 x, u, 방향 
+            fishes[input_list[j]] = (i, j//2)
+
+    to_eat = graph[0][0][0]
+    shark_d = graph[0][0][1]
+    shark = (0, 0, shark_d) 
+    graph[0][0] = (-1, shark_d)
+    fishes[to_eat] = ()
+    ate_list = []
+
+    def dfs(graph, shark, fishes, ate):
+        graph = copy.deepcopy(graph)
+        fishes = copy.deepcopy(fishes)
+
+        graph, fishes = fish_move(graph, fishes)
+        to_eat = shark_eat(graph, shark)
+        if to_eat==[] :
+            ate_list.append(ate)
+            return
+        sh_old_x = shark[0]
+        sh_old_y = shark[1]
+        sh_old_d = shark[2]
+        for candidate in to_eat:
+            x, y = candidate
+            new_sh_d = graph[x][y][1]
+            fish = graph[x][y][0]
+            fishes[fish] = ()
+            graph[x][y] = (-1, new_sh_d)
+            graph[sh_old_x][sh_old_y] = (0, 0)
+            shark = (x, y, new_sh_d)
+            ate += fish
+            dfs(graph, shark, fishes, ate)
+            ate -= fish
+            shark = (sh_old_x, sh_old_y, sh_old_d)
+            graph[sh_old_x][sh_old_y] = (-1, sh_old_d)
+            graph[x][y] = (fish, new_sh_d)
+            fishes[fish] = (x, y)
+
+    dfs(graph, shark, fishes, to_eat)
+    ate_list.sort(reverse=True)
+    return ate_list[0]
+
+def fish_move(graph, fishes):
+    move = [(-1, 0), (-1, -1), (0,-1), (1, -1), (1, 0), (1, 1), (0, 1), (-1, 1)]
+    for f, fish in enumerate(fishes):
+        if fish == () :
+            continue
+        x, y = fish
+        d = graph[x][y][1]
+        for i in range(d, d+8):
+            ni = i
+            if ni > 7:
+                ni -= 8
+            nx = x + move[ni][0]
+            ny = y + move[ni][1]
+            if 0<=nx<4 and 0<=ny<4 and graph[nx][ny][0] != -1 :
+                graph[x][y] = (f, ni)
+                other_fish = graph[nx][ny][0]
+                graph[nx][ny], graph[x][y] = graph[x][y], graph[nx][ny]
+                fishes[f] = (nx, ny)
+                if other_fish != 0 :
+                    fishes[other_fish] = (x, y)
+                break
+    return graph, fishes
+
+def shark_eat(graph, shark):
+    move = [(-1, 0), (-1, -1), (0,-1), (1, -1), (1, 0), (1, 1), (0, 1), (-1, 1)]
+    sh_x, sh_y, sh_d = shark
+    nx = sh_x
+    ny = sh_y
+    to_eat = []
+    while True:
+        nx = nx + move[sh_d][0]
+        ny = ny + move[sh_d][1]
+        if 0 <= nx < 4 and 0 <= ny < 4:
+            if graph[nx][ny][0] != 0 :
+                to_eat.append((nx, ny))
+        else:
+            break
+    return to_eat
+
+print(solution())
+
+