Merge pull request #41 from AlgoLeadMe/12-alstjr7437

12-alstjr7437

alstjr7437/BFS/백조의-호수.py

@@ -0,0 +1,88 @@
+from collections import deque
+import sys
+
+dx = [0,0,-1,1]
+dy = [1,-1,0,0]
+r, c = map(int, input().split())
+
+water1 = deque()
+water2 = deque()
+visited = [[False] * c for _ in range(r)]
+
+swan1 = deque()
+swan2 = deque()
+visited2 = [[False] * c for _ in range(r)]
+
+# 1. 전체 호수 만들기
+river = []
+for i in range(r):
+    river.append(list(input()))
+
+day_count = 0
+
+# 2. 백조 위치 찾기와 물 위치 찾기
+swan = []
+for x in range(c):
+    for y in range(r):
+        if river[y][x] == "L":
+            swan.append([y,x])
+            river[y][x] = "."
+        if river[y][x] == ".":
+            water1.append([y, x])
+            visited[y][x] = True
+
+# 3. 백조를 큐에 추가 
+swan1.append(swan[0])
+visited2[swan[0][0]][swan[0][1]] = True
+
+# 4. 하루에 한번씩 X 없애기(얼음 없애기)
+def break_ice():
+    # print("-------")
+    while water1:
+        y, x = water1.popleft()
+        # print(y, x, water1, water2)
+        river[y][x] = "."
+        for i in range(4):
+            nx = x + dx[i]
+            ny = y + dy[i]
+            if nx < 0 or nx >= c or ny < 0 or ny >= r:
+                continue
+            if not visited[ny][nx]:
+                if river[ny][nx] == ".":
+                    water1.append([ny,nx])
+                else :
+                    water2.append([ny,nx])
+                visited[ny][nx] = True
+
+# 5. 백조가 만나는지 체크하기
+def check_swan():
+    # print("-------")
+    while swan1 : 
+        y, x = swan1.popleft()
+        # print(x,y,swan1, swan2)
+        if y == swan[1][0] and x == swan[1][1]:
+            print(day_count)
+            sys.exit()
+        for i in range(4):
+            nx = x + dx[i]
+            ny = y + dy[i]
+            if nx < 0 or nx >= c or ny < 0 or ny >= r:
+                continue
+            if not visited2[ny][nx]:
+                if river[ny][nx] == "." and visited2[ny][nx] == False:
+                    swan1.append([ny,nx])
+                else :
+                    swan2.append([ny,nx])
+                visited2[ny][nx] = True
+    return False
+
+# 만날때까지 돌리기
+while 1:
+    break_ice()
+    water1 = water2
+    water2 = deque()
+
+    check_swan()
+    swan1 = swan2
+    swan2 = deque()
+    day_count += 1

alstjr7437/README.md

@@ -13,4 +13,4 @@
 | 9차시 | 2024.02.17 |  그리디  | <a href="https://www.acmicpc.net/problem/2138">전구와 스위치</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-6/pull/29 |
 | 10차시 | 2024.02.20 |  BFS/DFS  | <a href="https://www.acmicpc.net/problem/11725">트리의 부모 찾기</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-6/pull/33 |
 | 11차시 | 2024.02.23 |  해시  | <a href="https://school.programmers.co.kr/learn/courses/30/lessons/42579">베스트 앨범</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-6/pull/39 |
-
+| 12차시 | 2024.02.26 |  BFS  | <a href="https://www.acmicpc.net/problem/3197">백조의 호수</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-6/pull/41 |