Create fractional_knapsack.py

Author: abhisheks008

Knapsack/Fractional Knapsack/fractional_knapsack.py

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+# Python3 program to solve fractional
+# Knapsack Problem
+  
+# Problem Statement : Given weights and values of n items, 
+#                     we need to put these items in a 
+#                     knapsack of capacity W to get the 
+#                     maximum total value in the knapsack.
+
+# ----------------------------------------------------------------- 
+
+# Approach : Brute Force Method
+# Abhishek S, 2021
+
+# ----------------------------------------------------------------- 
+
+# Solution : Using the Brute Force method we can figure out the solution
+
+
+# This function returns the item values of the data class
+class ItemValue:
+  
+    """Item Value DataClass"""
+  
+    def __init__(self, wt, val, ind):
+        self.wt = wt
+        self.val = val
+        self.ind = ind
+        self.cost = val // wt
+  
+    def __lt__(self, other):
+        return self.cost < other.cost
+  
+# Greedy Approach
+  
+# this function is the main architecture to solve the program.  
+class FractionalKnapSack:
+  
+    """Time Complexity O(n log n)"""
+    def getMaxValue(wt, val, capacity):
+        """function to get maximum value """
+        iVal = []
+        for i in range(len(wt)):
+            iVal.append(ItemValue(wt[i], val[i], i))
+  
+        # sorting items by value
+        iVal.sort(reverse=True)
+  
+        totalValue = 0
+        for i in iVal:
+            curWt = int(i.wt)
+            curVal = int(i.val)
+            if capacity - curWt >= 0:
+                capacity -= curWt
+                totalValue += curVal
+            else:
+                fraction = capacity / curWt
+                totalValue += curVal * fraction
+                capacity = int(capacity - (curWt * fraction))
+                break
+        return totalValue
+  
+  
+# Driver Code
+if __name__ == "__main__":
+    wt = [10, 40, 20, 30]
+    val = [60, 40, 100, 120]
+    capacity = 50
+    print ("- Fractional Knapsack Problem using Brute Force Method - ")
+    print ("-----------------------------------------------------")
+    print ()
+    print ("The values given : ")
+    print (val)
+    print ("-----------------------------------------------------")
+    print ("The corresponding weights are :")
+    print (wt)
+    print ("-----------------------------------------------------")
+    print ("The maximum capacity can be : ")
+    print (capacity)
+    print ()
+    print ("-----------------------------------------------------")
+    print ()
+    print ("Output : ")
+    # Function call
+    maxValue = FractionalKnapSack.getMaxValue(wt, val, capacity)
+    print("Maximum value in Knapsack =", maxValue)
+
+    
+# -----------------------------------------------------------------   
+# Input given :
+# The values given : 
+# [60, 40, 100, 120]
+# -----------------------------------------------------
+# The corresponding weights are :
+# [10, 40, 20, 30]
+# -----------------------------------------------------
+# The maximum capacity can be : 
+# 50
+
+# -----------------------------------------------------
+# Output :
+# Maximum total value of the Knapsack : 
+# 240.0
+
+# -----------------------------------------------------------------   
+
+# Code contributed by, Abhishek Sharma, 2021