Merge pull request #2351 from Echo0701/master

更新背包问题理论基础多重背包的 Java 语言版本

problems/背包问题理论基础多重背包.md

@@ -165,7 +165,43 @@ int main() {
 
 ### Java：
 
+```Java
+import java.util.Scanner;
+class multi_pack{
+    public static void main(String [] args) {
+        Scanner sc = new Scanner(System.in);
 
+        /**
+         * bagWeight:背包容量
+         * n:物品种类
+         */
+        int bagWeight, n;
+        
+        //获取用户输入数据，中间用空格隔开，回车键换行
+        bagWeight = sc.nextInt();
+        n = sc.nextInt();
+        int[] weight = new int[n];
+        int[] value = new int[n];
+        int[] nums = new int[n];
+        for (int i = 0; i < n; i++) weight[i] = sc.nextInt();
+        for (int i = 0; i < n; i++) value[i] = sc.nextInt();
+        for (int i = 0; i < n; i++) nums[i] = sc.nextInt();
+
+        int[] dp = new int[bagWeight + 1];
+
+        //先遍历物品再遍历背包，作为01背包处理
+        for (int i = 0; i < n; i++) {
+            for (int j = bagWeight; j >= weight[i]; j--) {
+                //遍历每种物品的个数
+                for (int k = 1; k <= nums[i] && (j - k * weight[i]) >= 0; k++) {
+                    dp[j] = Math.max(dp[j], dp[j - k * weight[i]] + k * value[i]);
+                }
+            }
+        }
+        System.out.println(dp[bagWeight]);
+    }
+}
+```
 ### Python：
 
 ### Go：