# 迷宫(91%) n = int(input().strip()) a = [] label = -1 for i in range(n): a.append(list(input().strip())) visited = [[0] * n for i in range(n)] dirs = [(-1,0),(1,0),(0,-1),(0,1)] for i in range(n): for j in range(n): if a[i][j] == 'S': visited[i][j] = 1 queue = [(i,j,0)] while queue: tmp = queue.pop(0) for t in dirs: i_n = (tmp[0] + t[0])%n j_n = (tmp[1] + t[1])%n if visited[i_n][j_n] == 0 and a[i_n][j_n] != '#': visited[i_n][j_n] = 1 queue.append((i_n,j_n,tmp[2]+1)) if a[i_n][j_n]=='E': label = tmp[2]+1 break if label!=-1: break print(label) # 字符串(100%) s = list(input().strip()) stack = [] se = set([')',"<"]) for i in range(len(s)): if s[i] not in se: stack.append(s[i]) elif s[i]==')': tmp = stack.pop(-1) while tmp != "(": tmp = stack.pop(-1) else: if not stack: continue if stack[-1]=='(': continue else: stack.pop(-1) print(''.join(stack)) # 宝物,O(n2), 超时,9%?直接print(3) 18%??? from operator import itemgetter n = int(input().strip()) a = [] for i in range(n): a.append(list(map(int, input().strip().split()))) a.sort(key=itemgetter(0)) dp = [1]*n max_s = 1 for i in range(len(a)): maxm = 1 for j in range(i): if a[i][1] >= a[j][1]: tmp = dp[j] + 1 else: tmp = dp[j] if tmp > maxm: maxm = tmp dp[i] = maxm if dp[i] > max_s: max_s = dp[i] print(max_s)