2024-12-31

tgyuuAn/BFS/불!.py

@@ -0,0 +1,84 @@
+import sys
+
+def input(): return sys.stdin.readline().rstrip()
+
+R, C = map(int, input().split())
+start = (0, 0)
+fire = []
+
+## 보드를 만드는데, 가장자리를 도착 지점(*)으로 감싼다.
+board = [["*" for _ in range(C+2)]]
+for r in range(R):
+    _input = input()
+    row = ["*"]
+    for c, elem in enumerate(_input):
+        if elem == "J": start = (r+1, c+1)
+        elif elem == "F": fire.append((r+1, c+1))
+        row.append(elem)
+    row.append("*")
+    board.append(row)
+board.append(["*" for _ in range(C+2)])
+
+# for x in board: print(x)
+# 불이 퍼지는 위치를 먼저 계산한 후, 지훈이가 갈 수 있는 위치를 계산 함.
+
+dx = [0, 0, -1, 1]
+dy = [-1, 1, 0, 0]
+
+f = fire[:]
+f_visited = set(fire)
+
+j = [start]
+j_visited = {start,}
+
+answer = 1
+answer_flag = False
+while j:
+    temp_f = []
+    while f:
+        (now_r, now_c) = f.pop()
+
+        for dire in range(4):
+            new_r = now_r + dy[dire]
+            new_c = now_c + dx[dire]
+
+            if new_r < 0 or new_r >= R+2: continue
+            if new_c < 0 or new_c >= C+2: continue
+            if board[new_r][new_c] == "#": continue
+            if board[new_r][new_c] == "*": continue
+            if (new_r, new_c) in f_visited: continue
+
+            temp_f.append((new_r, new_c))
+            f_visited.add((new_r, new_c))
+
+    temp_j = []
+
+    while j:
+        (now_r, now_c) = j.pop()
+
+        for dire in range(4):
+            new_r = now_r + dy[dire]
+            new_c = now_c + dx[dire]
+
+            if new_r < 0 or new_r >= R+2: continue
+            if new_c < 0 or new_c >= C+2: continue
+            if board[new_r][new_c] == "#": continue
+            if (new_r, new_c) in j_visited: continue
+            if (new_r, new_c) in f_visited: continue
+
+            if board[new_r][new_c] == "*":
+                answer_flag = True
+                print(answer)
+                break
+
+
+            temp_j.append((new_r, new_c))
+            j_visited.add((new_r, new_c))
+
+        if answer_flag: break
+    if answer_flag: break
+    f = temp_f[:]
+    j = temp_j[:]
+    answer += 1
+
+else: print("IMPOSSIBLE")

tgyuuAn/README.md

@@ -87,4 +87,5 @@
 | 81차시 | 2024.11.15 |  이분 탐색  | <a href="https://www.acmicpc.net/problem/1701">Cubeeditor</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/255
 | 82차시 | 2024.11.22 |  희소 배열  | <a href="https://www.acmicpc.net/problem/17435">합성함수와 쿼리</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/257
 | 83차시 | 2024.12.01 |  수학 + 구현 | <a href="https://www.acmicpc.net/problem/1033">칵테일</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/259
+| 84차시 | 2024.12.31 |  BFS | <a href="https://www.acmicpc.net/problem/4179">불!</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/261
 ---