Add recursion and bfs problem solution

Author: roytravel

00. BOJ-Solutions/재귀/2448-별 찍기 - 11.py

@@ -0,0 +1,22 @@
+import sys
+sys.setrecursionlimit(10**9)
+input = sys.stdin.readline
+
+def star(r, c, N):
+    if N == 3:
+        graph[r][c] = "*"
+        graph[r+1][c-1] = "*"
+        graph[r+1][c+1] = "*"
+        for i in range(-2, 3):
+            graph[r+2][c+i] = "*"
+    else:
+        n = N // 2
+        star(r, c, n)
+        star(r+n, c-n, n)
+        star(r+n, c+n, n)
+
+N = int(input())
+graph = [[' ']*(N*2) for _ in range(N)]
+star(0, N-1, N)
+for row in graph:
+    print ("".join(row))

00. BOJ-Solutions/탐색/그래프 탐색/너비 우선 탐색/12851-숨바꼭질 2.py

@@ -0,0 +1,24 @@
+import sys
+from collections import deque
+input = sys.stdin.readline
+
+def bfs(start):
+    count = 0
+    queue = deque([start])
+    visited[start] = 1
+    while queue:
+        x = queue.popleft()
+        if x == K:
+            count += 1
+        for nx in [x-1, x+1, x*2]:
+            if 0<=nx<100001:
+                if not visited[nx] or visited[nx] >= visited[x]+1: # I don't get it why post condition is required?
+                    visited[nx] = visited[x]+1
+                    queue.append(nx)
+    return count
+
+N, K = map(int, input().split())
+visited = [0] * (100_001)
+count = bfs(N)
+print(visited[K]-1) # because it was started from 1.
+print(count)