수식 복원하기 풀이

Author: saebyeok0306

Programmers/Level3/[PCCP 기출문제] 4번 수식 복원하기.py

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+# PCCP 기출문제
+# https://school.programmers.co.kr/learn/courses/30/lessons/340210
+
+def transform_10_to_base(num:str, base):
+    num_int = int(num)
+    if num_int == 0:
+        return "0"
+    res = []
+    while num_int:
+        q,r = divmod(num_int, base)
+        num_int = q
+        res.append(str(r))
+        if num_int < base:
+            res.append(str(num_int))
+            break
+    return str(int("".join(res[::-1])))
+
+def solution(expressions):
+    split_expressions = [e.split() for e in expressions]
+    possible_base = list(range(2, 10))
+    
+    # 1. 불가능한 진법은 제거하기
+    for exp in split_expressions:
+        if exp[-1] == "X":
+            continue
+
+        remove_base = []
+        num1, op, num2, _, res = exp
+        for base in possible_base:
+            try:
+                _num1 = int(num1, base)
+                _num2 = int(num2, base)
+            except:
+                remove_base.append(base)
+                continue
+
+            if op == "+":
+                base_res = transform_10_to_base(str(int(_num1) + int(_num2)), base)
+            else:
+                base_res = transform_10_to_base(str(int(_num1) - int(_num2)), base)
+
+            if base_res != res:
+                remove_base.append(base)
+        
+        for rb in remove_base:
+            possible_base.remove(rb)
+    
+    predict = []
+    remove_base = set() # 불가능한 진법이 있는 경우, 예측된 다른 결과에서도 제거하기 위함
+    # 2. 가능한 진법으로 변환하기
+    for exp in split_expressions:
+        if exp[-1] != "X":
+            continue
+        
+        pred_result = [set()]
+        num1, op, num2, _, res = exp
+        for base in possible_base:
+            try:
+                _num1 = int(num1, base)
+                _num2 = int(num2, base)
+            except:
+                remove_base.add(base)
+                continue
+
+            if op == "+":
+                base_res = transform_10_to_base(str(int(_num1) + int(_num2)), base)
+            else:
+                base_res = transform_10_to_base(str(int(_num1) - int(_num2)), base)
+
+            pred_result[0].add(base)
+            pred_result.append((base_res, base))
+        
+        predict.append(pred_result)
+    
+    # 3. 불가능한 진법에 대한 결과 삭제하기
+    for pred_result in predict:
+        for base in remove_base:
+            if base in pred_result[0]:
+                for p in pred_result[1:]:
+                    if p[1] == base:
+                        pred_result.remove(p)
+                        pred_result[0].remove(base)
+    
+    # 4. 결과 출력하기
+    answer = []
+    idx = -1
+    for exp in split_expressions:
+        if exp[-1] != "X":
+            continue
+
+        idx += 1
+        num1, op, num2, _, _ = exp
+        pred = predict[idx]
+        pred_list = pred[1:]
+        
+        all_same = set()
+        for p in pred_list:
+            all_same.add(p[0])
+        
+        if len(all_same) == 1:
+            answer.append(f"{num1} {op} {num2} = {pred_list[0][0]}")
+            continue
+        else:
+            answer.append(f"{num1} {op} {num2} = ?")
+
+    return answer
+
+expressions = [
+    ["14 + 3 = 17", "13 - 6 = X", "51 - 5 = 44"],
+    ["1 + 1 = 2", "1 + 3 = 4", "1 + 5 = X", "1 + 2 = X"],
+    ["10 - 2 = X", "30 + 31 = 101", "3 + 3 = X", "33 + 33 = X"],
+    ["2 - 1 = 1", "2 + 2 = X", "7 + 4 = X", "5 - 5 = X"],
+    ["2 - 1 = 1", "2 + 2 = X", "7 + 4 = X", "8 + 4 = X"]
+]
+
+result = [
+    ["13 - 6 = 5"],
+    ["1 + 5 = ?", "1 + 2 = 3"],
+    ["10 - 2 = 4", "3 + 3 = 10", "33 + 33 = 110"],
+    ["2 + 2 = 4", "7 + 4 = ?", "5 - 5 = 0"],
+    ["2 + 2 = 4", "7 + 4 = 12", "8 + 4 = 13"]
+]
+
+for q in [0,1,2,3,4]:
+    qid = solution(expressions[q])
+    if qid == result[q]:
+        print(f'correct {qid}')
+    else:
+        print(f'incorrect {qid}')