CompleteKnapsack

Author: fluency03

Diff for: src/knapsack/CompleteKnapsack.java

@@ -0,0 +1,83 @@
+/**
+ * There are N objects and a bag with capacity of V. Evey type of object can be
+ * used with unlimited number of times.
+ * The ith object is having costs[i] and weights[i].
+ * Find out which objects can be put into the bag in order to have maximum value.
+ */
+
+
+public class CompleteKnapsack {
+
+    /**
+     * dp[i][v] = max{dp[i-1][v], dp[i][v-c[i]] + w[i]}
+     */
+    public int maxValue(int[] costs, int[] weights, int V) {
+        if (costs == null || weights == null) return 0;
+        int N = costs.length;
+        int[][] dp = new int[N + 1][V + 1];
+
+        for (int i=1; i<=N; i++) {
+            for (int v=1; v<=V; v++) {
+                if (v < costs[i-1]) {
+                    dp[i][v] = dp[i-1][v];
+                } else {
+                    dp[i][v] = Math.max(dp[i-1][v], dp[i][v - costs[i-1]] + weights[i-1]);
+                }
+            }
+        }
+        return dp[N][V];
+    }
+
+
+    /**
+     * dp[v] = max{dp[v], dp[v-c[i]] + w[i]}
+     */
+    public int maxValue2(int[] costs, int[] weights, int V) {
+        if (costs == null || weights == null) return 0;
+        int N = costs.length;
+        int[] dp = new int[V + 1];
+
+        for (int i=0; i<N; i++) {
+            for (int v=costs[i]; v<=V; v++) {
+                dp[v] = Math.max(dp[v], dp[v - costs[i]] + weights[i]);
+            }
+        }
+        return dp[V];
+    }
+
+
+    public static void main(String[] args) {
+        CompleteKnapsack slt = new CompleteKnapsack();
+
+        int[] costs = new int[]{};
+        int[] weights = new int[]{};
+        System.out.println(slt.maxValue(costs, weights, 10));
+        System.out.println(slt.maxValue2(costs, weights, 10));
+
+        costs = new int[]{2};
+        weights = new int[]{2};
+        System.out.println(slt.maxValue(costs, weights, 2));
+        System.out.println(slt.maxValue2(costs, weights, 2));
+
+        costs = new int[]{2};
+        weights = new int[]{2};
+        System.out.println(slt.maxValue(costs, weights, 3));
+        System.out.println(slt.maxValue2(costs, weights, 3));
+
+        costs = new int[]{2};
+        weights = new int[]{2};
+        System.out.println(slt.maxValue(costs, weights, 1));
+        System.out.println(slt.maxValue2(costs, weights, 1));
+
+
+
+
+
+    }
+
+
+    // procedure CompletePack(cost,weight)
+    // for v=cost..V
+    //     f[v]=max{f[v],f[v-c[i]]+w[i]}
+
+}