translation: Add Python and Java code for EN version (#1345)

* Add the intial translation of code of all the languages

* test

* revert

* Remove

* Add Python and Java code for EN version

en/codes/java/chapter_greedy/coin_change_greedy.java

@@ -0,0 +1,55 @@
+/**
+ * File: coin_change_greedy.java
+ * Created Time: 2023-07-20
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_greedy;
+
+import java.util.Arrays;
+
+public class coin_change_greedy {
+    /* Coin change: Greedy */
+    static int coinChangeGreedy(int[] coins, int amt) {
+        // Assume coins list is ordered
+        int i = coins.length - 1;
+        int count = 0;
+        // Loop for greedy selection until no remaining amount
+        while (amt > 0) {
+            // Find the smallest coin close to and less than the remaining amount
+            while (i > 0 && coins[i] > amt) {
+                i--;
+            }
+            // Choose coins[i]
+            amt -= coins[i];
+            count++;
+        }
+        // If no feasible solution is found, return -1
+        return amt == 0 ? count : -1;
+    }
+
+    public static void main(String[] args) {
+        // Greedy: can ensure finding a global optimal solution
+        int[] coins = { 1, 5, 10, 20, 50, 100 };
+        int amt = 186;
+        int res = coinChangeGreedy(coins, amt);
+        System.out.println("\ncoins = " + Arrays.toString(coins) + ", amt = " + amt);
+        System.out.println("The minimum number of coins required to make up " + amt + " is " + res);
+
+        // Greedy: cannot ensure finding a global optimal solution
+        coins = new int[] { 1, 20, 50 };
+        amt = 60;
+        res = coinChangeGreedy(coins, amt);
+        System.out.println("\ncoins = " + Arrays.toString(coins) + ", amt = " + amt);
+        System.out.println("The minimum number of coins required to make up " + amt + " is " + res);
+        System.out.println("In reality, the minimum number needed is 3, i.e., 20 + 20 + 20");
+
+        // Greedy: cannot ensure finding a global optimal solution
+        coins = new int[] { 1, 49, 50 };
+        amt = 98;
+        res = coinChangeGreedy(coins, amt);
+        System.out.println("\ncoins = " + Arrays.toString(coins) + ", amt = " + amt);
+        System.out.println("The minimum number of coins required to make up " + amt + " is " + res);
+        System.out.println("In reality, the minimum number needed is 2, i.e., 49 + 49");
+    }
+}

en/codes/java/chapter_greedy/fractional_knapsack.java

@@ -0,0 +1,59 @@
+/**
+ * File: fractional_knapsack.java
+ * Created Time: 2023-07-20
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_greedy;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/* Item */
+class Item {
+    int w; // Item weight
+    int v; // Item value
+
+    public Item(int w, int v) {
+        this.w = w;
+        this.v = v;
+    }
+}
+
+public class fractional_knapsack {
+    /* Fractional knapsack: Greedy */
+    static double fractionalKnapsack(int[] wgt, int[] val, int cap) {
+        // Create an item list, containing two properties: weight, value
+        Item[] items = new Item[wgt.length];
+        for (int i = 0; i < wgt.length; i++) {
+            items[i] = new Item(wgt[i], val[i]);
+        }
+        // Sort by unit value item.v / item.w from high to low
+        Arrays.sort(items, Comparator.comparingDouble(item -> -((double) item.v / item.w)));
+        // Loop for greedy selection
+        double res = 0;
+        for (Item item : items) {
+            if (item.w <= cap) {
+                // If the remaining capacity is sufficient, put the entire item into the knapsack
+                res += item.v;
+                cap -= item.w;
+            } else {
+                // If the remaining capacity is insufficient, put part of the item into the knapsack
+                res += (double) item.v / item.w * cap;
+                // No remaining capacity left, thus break the loop
+                break;
+            }
+        }
+        return res;
+    }
+
+    public static void main(String[] args) {
+        int[] wgt = { 10, 20, 30, 40, 50 };
+        int[] val = { 50, 120, 150, 210, 240 };
+        int cap = 50;
+
+        // Greedy algorithm
+        double res = fractionalKnapsack(wgt, val, cap);
+        System.out.println("The maximum value within the bag capacity is " + res);
+    }
+}

en/codes/java/chapter_greedy/max_capacity.java

@@ -0,0 +1,38 @@
+/**
+ * File: max_capacity.java
+ * Created Time: 2023-07-21
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_greedy;
+
+public class max_capacity {
+    /* Maximum capacity: Greedy */
+    static int maxCapacity(int[] ht) {
+        // Initialize i, j, making them split the array at both ends
+        int i = 0, j = ht.length - 1;
+        // Initial maximum capacity is 0
+        int res = 0;
+        // Loop for greedy selection until the two boards meet
+        while (i < j) {
+            // Update maximum capacity
+            int cap = Math.min(ht[i], ht[j]) * (j - i);
+            res = Math.max(res, cap);
+            // Move the shorter board inward
+            if (ht[i] < ht[j]) {
+                i++;
+            } else {
+                j--;
+            }
+        }
+        return res;
+    }
+
+    public static void main(String[] args) {
+        int[] ht = { 3, 8, 5, 2, 7, 7, 3, 4 };
+
+        // Greedy algorithm
+        int res = maxCapacity(ht);
+        System.out.println("The maximum capacity is " + res);
+    }
+}

en/codes/java/chapter_greedy/max_product_cutting.java

@@ -0,0 +1,40 @@
+/**
+ * File: max_product_cutting.java
+ * Created Time: 2023-07-21
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_greedy;
+
+import java.lang.Math;
+
+public class max_product_cutting {
+    /* Maximum product of cutting: Greedy */
+    public static int maxProductCutting(int n) {
+        // When n <= 3, must cut out a 1
+        if (n <= 3) {
+            return 1 * (n - 1);
+        }
+        // Greedy cut out 3s, a is the number of 3s, b is the remainder
+        int a = n / 3;
+        int b = n % 3;
+        if (b == 1) {
+            // When the remainder is 1, convert a pair of 1 * 3 into 2 * 2
+            return (int) Math.pow(3, a - 1) * 2 * 2;
+        }
+        if (b == 2) {
+            // When the remainder is 2, do nothing
+            return (int) Math.pow(3, a) * 2;
+        }
+        // When the remainder is 0, do nothing
+        return (int) Math.pow(3, a);
+    }
+
+    public static void main(String[] args) {
+        int n = 58;
+
+        // Greedy algorithm
+        int res = maxProductCutting(n);
+        System.out.println("The maximum product of division is " + res);
+    }
+}