[BOJ] 17144 미세먼지 안녕! (G4)

Author: poodlepoodle

최어진/8주차/260218.py

@@ -0,0 +1,104 @@
+# 백준 17144번: 미세먼지 안녕! (3회차)
+
+import sys
+
+input = sys.stdin.readline
+
+# R, C <= 50
+# T <= 10^3
+R, C, T = map(int, input().rstrip().split())
+maps = [list(map(int, input().rstrip().split())) for _ in range(R)]
+
+EMPTY = 0
+CLEANER = -1
+
+cleaner_r_top, cleaner_r_bottom = -1, -1
+for r in range(R):
+    if maps[r][0] == CLEANER:
+        cleaner_r_top, cleaner_r_bottom = r, r + 1
+        break
+
+# 1초 동안 일어나는 일
+#   1. 확산: 모든 칸마다 4개 방향 -> 4 * 50 * 50 <= 10^4
+#   2. 순환: 최대 모든 칸 < 10^4
+# 주어진 시간은 T초 < 10^3
+# 예상: 10^7~10^8 이내
+
+moves = [
+    [-1, 0],
+    [1, 0],
+    [0, -1],
+    [0, 1]
+]
+
+def is_empty(r, c):
+    return maps[r][c] == EMPTY
+
+def is_cleaner(r, c):
+    return (cleaner_r_top <= r <= cleaner_r_bottom) and c == 0
+
+def is_in_board(r, c):
+    return 0 <= r < R and 0 <= c < C
+
+def print_board():
+    for row in maps:
+        print(row)
+    print()
+
+def diffusion():
+    diffused_maps = [[0 for _ in range(C)] for _ in range(R)]
+
+    for r in range(R):
+        for c in range(C):
+            if is_cleaner(r, c): continue
+            if is_empty(r, c): continue
+
+            diffused_maps[r][c] += maps[r][c]
+            unit_diffusion = maps[r][c] // 5
+            for dr, dc in moves:
+                if is_in_board(r + dr, c + dc) and not is_cleaner(r + dr, c + dc):
+                    diffused_maps[r + dr][c + dc] += unit_diffusion
+                    diffused_maps[r][c] -= unit_diffusion
+
+    diffused_maps[cleaner_r_top][0], diffused_maps[cleaner_r_bottom][0] = -1, -1
+    return diffused_maps
+
+def circulation():
+    # upper circulation
+    for r in range(cleaner_r_top - 1, 0, -1):
+        maps[r][0] = maps[r - 1][0]
+    for c in range(C - 1):
+        maps[0][c] = maps[0][c + 1]
+    for r in range(cleaner_r_top):
+        maps[r][C - 1] = maps[r + 1][C - 1]
+    for c in range(C - 1, 1, -1):
+        maps[cleaner_r_top][c] = maps[cleaner_r_top][c - 1]
+    maps[cleaner_r_top][1] = 0
+
+    # lower circulation
+    for r in range(cleaner_r_bottom + 1, R - 1):
+        maps[r][0] = maps[r + 1][0]
+    for c in range(C - 1):
+        maps[R - 1][c] = maps[R - 1][c + 1]
+    for r in range(R - 1, cleaner_r_bottom, -1):
+        maps[r][C - 1] = maps[r - 1][C - 1]
+    for c in range(C - 1, 1, -1):
+        maps[cleaner_r_bottom][c] = maps[cleaner_r_bottom][c - 1]
+    maps[cleaner_r_bottom][1] = 0
+
+def count_dusts():
+    cnt = 0
+    for r in range(R):
+        for c in range(C):
+            if not is_cleaner(r, c):
+                cnt += maps[r][c]
+    return cnt
+
+for _ in range(T):
+    maps = diffusion()
+    # print_board()
+    circulation()
+    # print_board()
+    # print('------------')
+
+print(count_dusts())