algorithms lesson #8

Author: biblelamp

BerlinTelran/Algorithms/src/lesson8/Lesson8.java

@@ -0,0 +1,60 @@
+package lesson8;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * Algorithms. Lesson #8. Greedy algorithm
+ *
+ * @author Sergey Iryupin
+ * @version 17 Aug 2023
+ */
+
+public class Lesson8 {
+    public static void main(String[] args) {
+        // 1 задача - выбор задач
+        List<Integer> tasks = Arrays.asList(3, 2, 1, 4, 5, 3);
+        int maxTime = 10;
+        List<Integer> resolved = taskSelection(tasks, maxTime);
+        System.out.println(resolved);
+
+        // 2 задача - размен монет
+        List<Integer> coins = Arrays.asList(1, 5, 10, 25);
+        int amount = 63;
+        System.out.println(coinChange(coins, amount));
+    }
+
+    static List<Integer> taskSelection(List<Integer> tasks, int maxTime) {
+        List<Integer> result = new ArrayList<>();
+        int resultTime = 0;
+
+        LinkedList<Integer> sortedTasks = new LinkedList<>(tasks);
+        Collections.sort(sortedTasks);
+        while (resultTime < maxTime && maxTime - resultTime >= sortedTasks.peek()) {
+            int taskTime = sortedTasks.pop();
+            result.add(taskTime);
+            resultTime = resultTime + taskTime;
+        }
+        return result;
+    }
+
+    static List<Integer> coinChange(List<Integer> coins, int amount) {
+        List<Integer> result = new ArrayList<>();
+
+        Collections.sort(coins);
+        for (int i = coins.size() - 1; i >= 0; i--) {
+            while (amount >= coins.get(i)) {
+                amount = amount - coins.get(i);
+                result.add(coins.get(i));
+            }
+        }
+
+        if (amount == 0) {
+            return result;
+        }
+        return Collections.EMPTY_LIST;
+    }
+}