2022/sector/10/pyramid solution

2022/sector/10/pyramid/pyramid.cpp

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+#include <bits/stdc++.h>
+
+using namespace std;
+
+ifstream in("test.in");
+ofstream out("test.out");
+
+
+unordered_set<int> cardRequirements;
+
+
+// Pre-fill a set containing possible amounts of cards required to build towers
+void fillRequirements() {
+    cardRequirements.insert(2);
+    // At height 1:
+    int levelCards = 2;
+    int cards = 2;
+    // (1 <= n <= 10 * 9)
+    int stop = pow(10, 9);
+
+    // height > 1
+    while (cards <= stop) {
+        // cout << "calculating for cards " << cards << endl;
+        levelCards += 3;
+        cards += levelCards;
+        cardRequirements.insert(cards);
+    }
+}
+
+
+void solveTestCase() {
+    int cards;
+    in >> cards;
+    // cout << "here" << endl;
+
+    if (cards == 1) {
+        out << 0 << endl;
+        return;
+    }
+
+    int towerAmount = 0;
+    while (cards > 1) {
+        int cardsToUse;
+        // Go backwards in amount of cards and check if that amount can be used to build a valid tower
+        for (cardsToUse = cards; cardsToUse > 1; cardsToUse--) {
+            if (cardRequirements.count(cardsToUse) == 1) {
+                towerAmount++;
+                cards -= cardsToUse;
+                break;
+            }
+        }
+    }
+    out << towerAmount << endl;
+}
+
+
+int main() {
+    fillRequirements();
+
+    int t;
+    in >> t;
+
+    for (int i = 0; i < t; i++) {
+        solveTestCase();
+    }
+
+   return 0;
+}