2021-7-5【虾皮笔试】:
机器人题目:
我的思路:用dfs找出所有能到达终点的路径,再用前缀和数组求出每条路径的触底体力值minH(也就是从路径头走到路径尾会出现的最低体力值),最后求出所有路径触底体力值的最大值,如果最大值大于0,直接返回1;否则返回触底体力值-minH+1.
# 虾皮笔试-机器人 class Solution: def minimumInitHealth(self, rooms, startPoint, endPoint): col_total = len(rooms[0]) row_total = len(rooms) rooms_total = col_total * row_total # 记录访问过的 visited = [[False for _ in range(col_total)] for _ in range(row_total)] # res记录路径 res = [] def dfs(rooms, row, col, path, visited, res): # stop condition if (row == endPoint[0] and col == endPoint[1])&nbs***bsp;len(path) == rooms_total: if row == endPoint[0] and col == endPoint[1]: temp = path[:] temp.append(rooms[row][col]) res.append(temp) return # bound if row >= row_total&nbs***bsp;row < 0&nbs***bsp;col >= col_total&nbs***bsp;col < 0&nbs***bsp;visited[row][col]: return # 回溯 visited[row][col] = True path.append(rooms[row][col]) dfs(rooms, row + 1, col, path, visited, res) dfs(rooms, row - 1, col, path, visited, res) dfs(rooms, row, col + 1, path, visited, res) dfs(rooms, row, col - 1, path, visited, res) path.pop() visited[row][col] = False dfs(rooms, startPoint[0], startPoint[1], [], visited, res) print('所有路径:', res) minH = [] # 求出所有路径体力的前缀和 for path in res: sum_ = [0] for value in path: sum_.append(sum_[-1]+value) minH.append(min(sum_)) # 找出最大的触底体力 if max(minH) < 0: return -max(minH)+1 else: return 1 if __name__ == '__main__': s = Solution() # 测试用例 rooms1 = [[-2, -3, 3], [-5, -10, 1], [10, 30, -5]] rooms3 = [[-2, -1, 1], [-5, 1, -10], [3, 1, -1]] rooms2 = [[2, 3, 3], [5, 10, 1], [10, 30, 5]] start = [0, 0] end = [2, 2] res = s.minimumInitHealth(rooms3, start, end) print(res)
程序还有很多可以优化的地方,欢迎批评指正。
楼主因为忘记考虑路径和大于0的情况才过了60。。发现的时候已经晚了。。。。
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