Merge pull request #701 from AlgorithmWithGod/lkhyun

[20250820] B형 / SWEA / 온라인마트 / 이강현

Author: ShinHeeEul

lkhyun/202508/20 B형 SWEA 온라인마트.md

@@ -0,0 +1,152 @@
+```java
+import java.util.*;
+
+class UserSolution
+{
+    static class Product implements Comparable<Product>{
+        int mID;
+        int mPrice;
+
+        Product(int mID, int mPrice){
+            this.mID = mID;
+            this.mPrice = mPrice;
+        }
+        @Override
+        public int compareTo(Product other){
+            if(this.mPrice == other.mPrice){
+                return Integer.compare(this.mID, other.mID);
+            }else{
+                return Integer.compare(this.mPrice, other.mPrice);
+            }
+        }
+    }
+    
+    static class ProductInfo{
+        int mCategory;
+        int mCompany;
+        
+        ProductInfo(int mCategory, int mCompany){
+            this.mCategory = mCategory;
+            this.mCompany = mCompany;
+        }
+    }
+    
+    static Map<Integer, ProductInfo> productInfoByID;
+    static Map<Integer, Product> productByID;
+    static TreeSet<Product>[][] productByCateCom;
+    static int[][] diff;
+    
+    public void init()
+    {
+        productInfoByID = new HashMap<>();
+        productByID = new HashMap<>();
+        productByCateCom = new TreeSet[6][6];
+        for (int i = 1; i <= 5; i++) {
+            for (int j = 1; j <= 5; j++) {
+                productByCateCom[i][j] = new TreeSet<>();
+            }
+        }
+        diff = new int[6][6];
+    }
+
+    public int sell(int mID, int mCategory, int mCompany, int mPrice)
+    {
+        Product newProduct = new Product(mID, mPrice - diff[mCategory][mCompany]);
+        ProductInfo newProductInfo = new ProductInfo(mCategory, mCompany);
+        
+        productInfoByID.put(mID, newProductInfo);
+        productByID.put(mID, newProduct);
+        productByCateCom[mCategory][mCompany].add(newProduct);
+
+        return productByCateCom[mCategory][mCompany].size();
+    }
+
+    public int closeSale(int mID)
+    {
+        if(!productInfoByID.containsKey(mID)) return -1;
+
+        ProductInfo info = productInfoByID.get(mID);
+        Product product = productByID.get(mID);
+        
+        int realPrice = product.mPrice + diff[info.mCategory][info.mCompany];
+        
+        productByCateCom[info.mCategory][info.mCompany].remove(product);
+        productInfoByID.remove(mID);
+        productByID.remove(mID);
+        
+        return realPrice;
+    }
+
+    public int discount(int mCategory, int mCompany, int mAmount)
+    {
+        diff[mCategory][mCompany] -= mAmount;
+        
+        TreeSet<Product> categoryProducts = productByCateCom[mCategory][mCompany];
+        
+        while (!categoryProducts.isEmpty()) {
+            Product first = categoryProducts.first();
+            if (first.mPrice + diff[mCategory][mCompany] <= 0) {
+                categoryProducts.pollFirst();
+                productInfoByID.remove(first.mID);
+                productByID.remove(first.mID);
+            } else {
+                break;
+            }
+        }
+        
+        return categoryProducts.size();
+    }
+
+    Solution.RESULT show(int mHow, int mCode)
+    {
+        Solution.RESULT res = new Solution.RESULT();
+        res.cnt = 0;
+        
+        TreeSet<Product> candidates = new TreeSet<>((p1, p2) -> {
+            int price1 = p1.mPrice + diff[productInfoByID.get(p1.mID).mCategory][productInfoByID.get(p1.mID).mCompany];
+            int price2 = p2.mPrice + diff[productInfoByID.get(p2.mID).mCategory][productInfoByID.get(p2.mID).mCompany];
+            
+            if (price1 == price2) {
+                return Integer.compare(p1.mID, p2.mID);
+            }
+            return Integer.compare(price1, price2);
+        });
+        
+        for (int i = 1; i <= 5; i++) {
+            if (mHow == 1 && i != mCode) continue;
+            
+            for (int j = 1; j <= 5; j++) {
+                if (mHow == 2 && j != mCode) continue;
+                
+                TreeSet<Product> categoryProducts = productByCateCom[i][j];
+                if (categoryProducts.isEmpty()) continue;
+                
+                for (Product p : categoryProducts) {
+                    int realPrice = p.mPrice + diff[i][j];
+                    if (realPrice <= 0) continue;
+                    
+                    if (candidates.size() < 5) {
+                        candidates.add(p);
+                    } else {
+                        Product last = candidates.last();
+                        int lastPrice = last.mPrice + diff[productInfoByID.get(last.mID).mCategory][productInfoByID.get(last.mID).mCompany];
+                        
+                        if (realPrice < lastPrice || (realPrice == lastPrice && p.mID < last.mID)) {
+                            candidates.pollLast();
+                            candidates.add(p);
+                        } else {
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+        
+        for (Product p : candidates) {
+            res.IDs[res.cnt++] = p.mID;
+        }
+        
+        return res;
+    }
+}
+```