Create AvtoBus Explanation.txt

Author: MathProgrammer

2022/Contests/Div 2/792/Explanations/AvtoBus Explanation.txt

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+When we want to maximize the number of buses, we will try to maximise the number of 4's.
+While trying to minimize, we will try to maximize the number of 6's. 
+
+There is no answer possible if N = 1, 3 (mod 4). 
+
+There are only 2 cases where an answer exists. 
+N = 0, 2 (mod 4)
+
+-----
+
+void solve()
+{
+    long long no_of_wheels;
+    cin >> no_of_wheels;
+
+    long long minimum, maximum;
+    switch(no_of_wheels%4)
+    {
+        case 0: maximum = no_of_wheels/4;
+                minimum = 2*(no_of_wheels/12) + (no_of_wheels%12 == 6 ? (no_of_wheels%12)/6 : (no_of_wheels%12)/4);
+                          break;
+
+        case 2: if(no_of_wheels == 2)
+                {
+                    cout << "-1\n";
+                    return;
+                }
+                maximum = 1 + (no_of_wheels - 6)/4;
+                no_of_wheels -= 6;
+                minimum = 1 + 2*(no_of_wheels/12) + (no_of_wheels%12 == 6 ? (no_of_wheels%12)/6 : (no_of_wheels%12)/4);
+                break;
+
+        default: cout << "-1\n";
+                 return;
+    }
+
+    cout << minimum << " " << maximum << "\n";
+}