Merge branch 'main' into 76-tgyuuAn

H0ngJu/DFS/트리의 지름.py

@@ -0,0 +1,28 @@
+import sys
+sys.setrecursionlimit(10**9)
+def input() : return sys.stdin.readline().rstrip()
+
+n = int(input())
+tree = [[] for _ in range(n+1)]
+visited = [-1] * (n+1)
+visited[1] = 0
+
+for i in range(n-1):
+    v, u, w = map(int, input().split())
+    tree[v].append((u, w))
+    tree[u].append((v, w))
+
+def dfs(start, dis):
+    for node, node_dis in tree[start]:
+        if visited[node] == -1:
+            visited[node] = dis + node_dis
+            dfs(node, dis + node_dis)
+
+dfs(1,0)
+
+far_node = visited.index(max(visited))
+visited = [-1] * (n+1)
+visited[far_node] = 0
+dfs(far_node, 0)
+
+print(max(visited))

H0ngJu/README.md

@@ -28,5 +28,6 @@
 | 24차시 | 2024.08.17 | BFS | [아기상어](https://www.acmicpc.net/problem/16236) | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/233 |
 | 25차시 | 2024.08.17 | DFS | [친구비](https://www.acmicpc.net/problem/16562) | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/234 |
 | 26차시 | 2024.08.24 | 그리디 | [신입사원](https://www.acmicpc.net/problem/1946) | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/237 |
-
+| 27차시 | 2024.08.27 | DFS | [트리의 지름](https://www.acmicpc.net/problem/1967) | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/240 |
+| 28차시 | 2024.09.04 | 벨만포드 | [타임머신](https://www.acmicpc.net/problem/11657) | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/244 |
 ---

H0ngJu/벨만포드/타임머신.py

@@ -0,0 +1,36 @@
+import sys
+
+INF = 1e8
+
+def input() : return sys.stdin.readline().rstrip()
+
+N, M = map(int, input().split())
+bus = [[] for _ in range(N+1)]
+distance = [INF] * (N+1)
+
+for i in range(M):
+    A, B, C = map(int, input().split())
+    bus[A].append([B, C])
+
+def BellmanFord(start):
+    distance[start] = 0
+
+    for i in range(N):
+        for j in range(1, N+1):
+            for n, w in bus[j]:
+                if distance[j] != INF and distance[n] > distance[j] + w:
+                    distance[n] = distance[j] + w
+                    if i == N-1:
+                        return True
+    return False
+
+check_negative = BellmanFord(1)
+
+if check_negative:
+    print("-1")
+else:
+    for i in range(2, N+1):
+        if distance[i] == INF:
+            print("-1")
+        else:
+            print(distance[i])

tgyuuAn/BFS/Rain (Small).py

@@ -0,0 +1,53 @@
+from collections import deque
+import sys
+
+def input(): return sys.stdin.readline().rstrip()
+
+dx = [0, 0, -1, 1]
+dy = [-1, 1, 0, 0]
+
+T = int(input())
+
+for test_idx in range(T):
+    row, col = map(int, input().split())
+    board = [list(map(int,input().split())) for _ in range(row)]
+    new_board = [[0 for _ in range(col)] for _ in range(row)]
+
+    for height in range(1, 1001):
+        for start_row in range(row):
+            for start_col in range(col):
+                if board[start_row][start_col] >= height: continue
+
+                deq = deque()
+                deq.append((start_row, start_col))
+                history = {(start_row, start_col),}
+
+                visited = set()
+                visited.add((start_row, start_col))
+
+                while deq:
+                    now_row, now_col = deq.popleft()
+
+                    # 가장자리에 물이 흘렀다는 것이므로 break
+                    if now_row in (0, row-1): break
+                    if now_col in (0, col-1): break
+
+                    for dir in range(4):
+                        new_row = now_row + dy[dir]
+                        new_col = now_col + dx[dir]
+
+                        if new_row < 0 or new_row >= row: continue
+                        if new_col < 0 or new_col >= col: continue
+                        if (new_row, new_col) in visited: continue
+                        if board[new_row][new_col] >= height: continue
+
+                        deq.append((new_row, new_col))
+                        history.add((new_row, new_col))
+                        visited.add((new_row, new_col))
+
+                    # 가장자리에 물이 흐르지 않아 break되지 않았으면,
+                else:
+                    for history_row, history_col in history:
+                        new_board[history_row][history_col] = height - board[history_row][history_col]
+
+    print(f"Case #{test_idx+1}: {sum([sum(row) for row in new_board])}")

tgyuuAn/DP/산 모양 타일링.py

@@ -0,0 +1,19 @@
+def solution(n, tops):
+    top = set()
+    DIV = 10_007
+
+    count = 0
+    for idx, element in enumerate(tops):
+        if element==1: 
+            count += 1
+            top.add(2*(idx+1)+count)
+
+    DP = [0 for _ in range((n*2)+1+count+1)]
+    DP[1] = 1
+    DP[2] = 2
+
+    for now_idx in range(3,len(DP)):
+        if (now_idx-1) in top: DP[now_idx] = (DP[now_idx-3] % DIV) + (DP[now_idx-1] % DIV) % DIV
+        else: DP[now_idx] = (DP[now_idx-2] % DIV) + (DP[now_idx-1] % DIV) % DIV
+
+    return DP[-1] % DIV

tgyuuAn/README.md

@@ -79,5 +79,8 @@
 | 70차시 | 2024.08.16 |  스택  | <a href="https://www.acmicpc.net/problem/22866">탑 보기</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/232
 | 71차시 | 2024.08.20 |  다익스트라  | <a href="https://www.acmicpc.net/problem/24042">다익스트라</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/235
 | 72차시 | 2024.08.23 |  DFS + 트리  | <a href="https://www.acmicpc.net/problem/20188">등산 마니아</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/238
+| 73차시 | 2024.08.26 |  BFS  | <a href="https://www.acmicpc.net/problem/14324">Rain (Small)</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/239
+| 74차시 | 2024.08.30 |  BFS  | <a href="https://www.acmicpc.net/problem/11967">불 켜기</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/242
+| 75차시 | 2024.09.02 |  DP  | <a href="https://school.programmers.co.kr/learn/courses/30/lessons/258705">산 모양 타일링</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/243
 | 76차시 | 2024.09.06 |  DFS + 트리  | <a href="https://school.programmers.co.kr/learn/courses/30/lessons/150367">표현 가능한 이진트리</a> | https://github.com/AlgoLeadMe/AlgoLeadMe-1/pull/246
 ---

tgyuuAn/완전 탐색/불 켜기.py

@@ -0,0 +1,46 @@
+from collections import deque, defaultdict
+import sys
+
+def input(): return sys.stdin.readline().rstrip()
+
+N, M = map(int, input().split())
+board = [[False for _ in range(N+1)] for _ in range(N+1)]
+board[1][1] = True
+
+switch = defaultdict(list)
+
+for _ in range(M):
+    x, y, a, b = map(int, input().split())
+    switch[(x, y)].append((a,b))
+
+deq = deque()
+deq.append((1,1))
+dx = [0, 0, -1, 1]
+dy = [-1, 1, 0, 0]
+visited = {(1, 1),}
+dedicates = {(1, 1),}
+
+while deq:
+    now_x, now_y = deq.popleft()
+
+    for turn_on in switch[(now_x, now_y)]:
+        if turn_on not in dedicates:    # <<<------- 이 코드 한줄에 3시간 날림
+            dedicates.add(turn_on)
+
+            if turn_on in visited: 
+                deq.append(turn_on)
+
+    for dir in range(4):
+        new_x = now_x + dx[dir]
+        new_y = now_y + dy[dir]
+
+        if new_x <= 0 or new_x >= N+1: continue
+        if new_y <= 0 or new_y >= N+1: continue
+        if (new_x, new_y) in visited: continue
+
+        visited.add((new_x, new_y))
+
+        if (new_x, new_y) in dedicates:
+            deq.append((new_x, new_y))
+
+print(len(dedicates))