| [프로그래머스, python3] 다리를 지나는 트럭 | |
| 난이도 | Level 2 |
| 분류 | 스택/큐 |
| programmers.co.kr/learn/courses/30/lessons/42583 | |
문제 설명
트럭 여러 대가 강을 가로지르는 일 차선 다리를 정해진 순으로 건너려 합니다. 모든 트럭이 다리를 건너려면 최소 몇 초가 걸리는지 알아내야 합니다. 트럭은 1초에 1만큼 움직이며, 다리 길이는 bridge_length이고 다리는 무게 weight까지 견딥니다.
※ 트럭이 다리에 완전히 오르지 않은 경우, 이 트럭의 무게는 고려하지 않습니다.
예를 들어, 길이가 2이고 10kg 무게를 견디는 다리가 있습니다. 무게가 [7, 4, 5, 6]kg인 트럭이 순서대로 최단 시간 안에 다리를 건너려면 다음과 같이 건너야 합니다.
| 경과 시간 | 다리를 지난 트럭 | 다리를 건너는 트럭 | 대기 트럭 |
| 0 | [] | [] | [7,4,5,6] |
| 1~2 | [] | [7] | [4,5,6] |
| 3 | [7] | [4] | [5,6] |
| 4 | [7] | [4,5] | [6] |
| 5 | [7,4] | [5] | [6] |
| 6~7 | [7,4,5] | [6] | [] |
| 8 | [7,4,5,6] | [] | [] |
따라서, 모든 트럭이 다리를 지나려면 최소 8초가 걸립니다.
solution 함수의 매개변수로 다리 길이 bridge_length, 다리가 견딜 수 있는 무게 weight, 트럭별 무게 truck_weights가 주어집니다. 이때 모든 트럭이 다리를 건너려면 최소 몇 초가 걸리는지 return 하도록 solution 함수를 완성하세요.
제한 조건
- bridge_length는 1 이상 10,000 이하입니다.
- weight는 1 이상 10,000 이하입니다.
- truck_weights의 길이는 1 이상 10,000 이하입니다.
- 모든 트럭의 무게는 1 이상 weight 이하입니다.
입출력 예
| bridge_length | weight | truck_weights | return |
| 2 | 10 | [7,4,5,6] | 8 |
| 100 | 100 | [10] | 101 |
| 100 | 100 | [10,10,10,10,10,10,10,10,10,10] | 110 |
소스코드
- deque를 활용
- bridge_state_dQ의 경우에는 bridge_length만큼의 크기를 가지며 각각의 위치에 트럭이 있는지 없는지에 대한 상태를 나타낸다. (0: 트럭이 존재하지 않음, >0: 트럭이 존재
- bridge로 들어오는 트럭 무게를 견딜 수 있는지 없는지를 파악
- (bridge의 총 트럭무게 - bridge에서 나가는 트럭무게 + bridge로 들어오는 트럭무게) > weight
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from collections import deque
def solution(bridge_length, weight, truck_weights):
time = 1
truck_weights_dQ = deque(truck_weights)
bridge_state_dQ = deque([0] * bridge_length)
truck_in = truck_weights_dQ.popleft()
bridge_state_dQ[-1] = truck_in
weight_sum = truck_in
while truck_weights_dQ:
if weight_sum - bridge_state_dQ[0] + truck_weights_dQ[0] > weight:
truck_out = bridge_state_dQ.popleft()
bridge_state_dQ.append(0)
weight_sum -= truck_out
time = time + 1
else:
truck_out = bridge_state_dQ.popleft()
truck_in = truck_weights_dQ.popleft()
bridge_state_dQ.append(truck_in)
weight_sum = weight_sum - truck_out + truck_in
time = time + 1
time = time + bridge_length
return time
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분석
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from collections import deque
def solution(bridge_length, weight, truck_weights):
time = 1
truck_weights_dQ = deque(truck_weights)
bridge_state_dQ = deque([0] * bridge_length)
print(f'truck_weights_dQ: {truck_weights_dQ}')
print(f'bridge_state_dQ: {bridge_state_dQ}')
truck_in = truck_weights_dQ.popleft()
bridge_state_dQ[-1] = truck_in
weight_sum = truck_in
while truck_weights_dQ:
print(f'bridge_state_dQ: {bridge_state_dQ}')
print(f'time: {time}, weight_sum: {weight_sum}, bridge_state_dQ[0]: {bridge_state_dQ[0]}, truck_weights_dQ[0]: {truck_weights_dQ[0]} ')
print(f'{weight_sum - bridge_state_dQ[0] + truck_weights_dQ[0] > weight:}')
print('-' * 60)
if weight_sum - bridge_state_dQ[0] + truck_weights_dQ[0] > weight:
truck_out = bridge_state_dQ.popleft()
bridge_state_dQ.append(0)
weight_sum -= truck_out
time = time + 1
else:
truck_out = bridge_state_dQ.popleft()
truck_in = truck_weights_dQ.popleft()
bridge_state_dQ.append(truck_in)
weight_sum = weight_sum - truck_out + truck_in
time = time + 1
print(f'time: {time}, bridge_length: {bridge_length}')
time = time + bridge_length
return time
if __name__ == "__main__":
print('-' * 40)
case = 3
bridge_length = [2,100,100]
weight = [10,100,100]
truck_weights = [[7,4,5,6],[10],[10,10,10,10,10,10,10,10,10,10]]
correct_answer = [8,101,110]
for i in range(case):
print(f"<<<<< case {i} >>>>>")
answer = solution(bridge_length[i],weight[i],truck_weights[i])
print('answer :' , answer, '/ correct_answer :' , correct_answer[i])
if correct_answer[i] == answer:
print(f'테스트 {i}를 통과하였습니다.')
else:
print(f'테스트 {i}를 통과하지 못했습니다.')
print('-' * 40)
----------------------------------------
<<<<< case 0 >>>>>
truck_weights_dQ: deque([7, 4, 5, 6])
bridge_state_dQ: deque([0, 0])
bridge_state_dQ: deque([0, 7])
time: 1, weight_sum: 7, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 4
True
------------------------------------------------------------
bridge_state_dQ: deque([7, 0])
time: 2, weight_sum: 7, bridge_state_dQ[0]: 7, truck_weights_dQ[0]: 4
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 4])
time: 3, weight_sum: 4, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 5
False
------------------------------------------------------------
bridge_state_dQ: deque([4, 5])
time: 4, weight_sum: 9, bridge_state_dQ[0]: 4, truck_weights_dQ[0]: 6
True
------------------------------------------------------------
bridge_state_dQ: deque([5, 0])
time: 5, weight_sum: 5, bridge_state_dQ[0]: 5, truck_weights_dQ[0]: 6
False
------------------------------------------------------------
time: 6, bridge_length: 2
answer : 8 / correct_answer : 8
테스트 0를 통과하였습니다.
----------------------------------------
<<<<< case 1 >>>>>
truck_weights_dQ: deque([10])
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
time: 1, bridge_length: 100
answer : 101 / correct_answer : 101
테스트 1를 통과하였습니다.
----------------------------------------
<<<<< case 2 >>>>>
truck_weights_dQ: deque([10, 10, 10, 10, 10, 10, 10, 10, 10, 10])
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10])
time: 1, weight_sum: 10, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10])
time: 2, weight_sum: 20, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10])
time: 3, weight_sum: 30, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 10])
time: 4, weight_sum: 40, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 10, 10])
time: 5, weight_sum: 50, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 10, 10, 10])
time: 6, weight_sum: 60, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 10, 10, 10, 10])
time: 7, weight_sum: 70, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 10, 10, 10, 10, 10])
time: 8, weight_sum: 80, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
bridge_state_dQ: deque([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 10, 10, 10, 10, 10, 10])
time: 9, weight_sum: 90, bridge_state_dQ[0]: 0, truck_weights_dQ[0]: 10
False
------------------------------------------------------------
time: 10, bridge_length: 100
answer : 110 / correct_answer : 110
테스트 2를 통과하였습니다.
----------------------------------------
Process finished with exit code 0
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