adding dp code for tsp

tsp.py

@@ -0,0 +1,95 @@
+import copy
+
+distancematrix = [
+    [0, 7.33, 9, 12],
+    [7.33, 0, 6.43, 4.2],
+    [9, 6.43, 0, 8],
+    [12, 4.2, 8, 0]
+]
+
+nodekeys = [0,1,2,3]
+start = nodekeys[0]
+
+endpoints = nodekeys[1:]
+
+dp = {}
+
+for i in endpoints:
+    dp[(start,i), i] = distancematrix[start][i]
+
+print(dp)
+
+
+# def tspsolve(nodekeys, distancematrix, start):
+#     path = [start]
+#     #get next city to visit and add to the list
+
+
+#     return path
+
+
+def dpcost(currset, end, distancematrix):
+    currset = tuple(currset)
+    if (currset,end) in dp.keys():
+        return dp[currset,end]
+
+    # pathnew = dict()
+
+    setnew = copy.deepcopy(list(currset))
+    setnew.remove(end)
+    setnew = tuple(setnew)
+    minlist = []
+    for j in currset:
+        if j != end and j!=start:
+            minlist.append(dpcost(setnew,j,distancematrix) + distancematrix[j][end])
+
+    minimum = min(minlist)
+
+    dp[currset,end] = minimum
+
+    return dp[currset,end]
+
+def createdp(currset,start = 0):
+    for i in currset:
+        if i != start:
+            dpcost(currset,i, distancematrix)
+
+def findpath(distancematrix, dp, currset, path = [], start= 0):
+    currsetstart = tuple(currset)
+    currset.remove(start)
+    prevval = start
+    path.append(start)
+    while(len(currset) > 1):
+
+        minimum = dp[currsetstart,currset[0]] + distancematrix[currset[0]][prevval]
+        minval = currset[0]
+        for i in currset:
+            if(minimum > dp[currsetstart,i] + distancematrix[i][prevval]):
+                minimum = dp[currsetstart,i] + distancematrix[i][prevval]
+                minval = i
+        path.append(minval)
+        currsetstart = copy.deepcopy(list(currsetstart))
+        currsetstart.remove(minval)
+        currsetstart = tuple(currsetstart)
+        currset.remove(minval)
+        prevval = minval
+
+    path.append(currset[0])
+    path.append(start)
+    path.reverse()
+    return path
+
+
+
+createdp(nodekeys)
+print(findpath(distancematrix,dp,nodekeys, []))
+
+
+
+
+
+
+
+
+print(dp)
+