MaximumBandwidthGraphTheory/MinHeap.py at main · alekhyaduba/MaximumBandwidthGraphTheory · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
import math


class MinHeap:

    def __init__(self, numOfVertices):
        self.numVertices = numOfVertices
        self.position_of_vertex = [-1 for i in range(numOfVertices)]
        self.value_at_position = []
        self.vertex_at_position = []

    def __int__(self, arr):
        self.numVertices = len(arr)
        self.position_of_vertex = [i for i in range(self.numVertices)]
        self.value_at_position = arr
        self.vertex_at_position = [i for i in range(self.numVertices)]

    def __len__(self):
        return len(self.vertex_at_position)

    def getPosition(self, vertex):
        return self.position_of_vertex[vertex]

    def minimum(self):
        return self.vertex_at_position[0], self.value_at_position[0]

    def findParentPosition(self, position):
        if position == 0:
            return -1
        return int((position - 1) / 2)

    def getVertexAtPosition(self, position):
        return self.vertex_at_position[position]

    def findSmallestChildPosition(self, position):

        if (2 * position) + 1 <= len(self.value_at_position) - 1:
            childPositionLeft = (2 * position) + 1
            if childPositionLeft + 1 <= len(self.value_at_position) - 1:
                childPositionRight = childPositionLeft + 1
            else:
                childPositionRight = -1
            valLeft = self.value_at_position[childPositionLeft]
            valRight = self.value_at_position[childPositionRight]
            if valLeft <= valRight:
                return childPositionLeft
            else:
                return childPositionRight
        else:
            return -1

    def updatePosition(self, vertex, position):
        self.position_of_vertex[vertex] = position

    def getValue(self, vertex_name):
        return self.value_at_position[self.getPosition(vertex_name)]

    def swap(self, position1, position2):
        self.vertex_at_position[position1], self.vertex_at_position[position2] = self.vertex_at_position[position2], \
                                                                                 self.vertex_at_position[position1]
        self.value_at_position[position1], self.value_at_position[position2] = self.value_at_position[position2], \
                                                                               self.value_at_position[position1]
        self.updatePosition(self.vertex_at_position[position1], position1)
        self.updatePosition(self.vertex_at_position[position2], position2)

    def insert(self, vertex_name, value):
        self.value_at_position.append(value)
        self.vertex_at_position.append(vertex_name)
        self.updatePosition(vertex_name, len(self.value_at_position) - 1)
        self.heapify(len(self.value_at_position) - 1)

    def delete(self, vertex_name):
        vertex_position = self.getPosition(vertex_name)
        end_position = len(self.value_at_position) - 1
        self.swap(vertex_position, end_position)

        # self.value_at_position = self.value_at_position[:-1]
        # self.vertex_at_position = self.vertex_at_position[:-1]

        self.value_at_position.pop()
        self.vertex_at_position.pop()
        self.updatePosition(vertex_name, -1)

        if len(self.value_at_position) > 0:
            self.heapify(vertex_position)

    def heapify(self, position):
        heapify_top = False
        parent_position = self.findParentPosition(position)

        while parent_position >= 0 and position <= len(self.value_at_position) - 1:

            if self.value_at_position[parent_position] > self.value_at_position[position]:
                heapify_top = True

                # update vertex and values at both positions
                self.swap(position, parent_position)

                position = parent_position
                parent_position = self.findParentPosition(position)
            else:
                break
        if not heapify_top:
            childPosition = self.findSmallestChildPosition(position)

            while childPosition >= 0:
                bottomHeapify = False

                if self.value_at_position[position] > self.value_at_position[childPosition]:
                    bottomHeapify = True
                    self.swap(position, childPosition)
                    position = childPosition
                    childPosition = self.findSmallestChildPosition(position)
                # else:
                #     childPosition = childPosition + 1
                #     if childPosition <= len(self.value_at_position) - 1:
                #         if self.value_at_position[position] < self.value_at_position[childPosition]:
                #             bottomHeapify = True
                #             self.swap(position, childPosition)
                #             position = childPosition
                #             childPosition = self.findGreatestChildPosition(position)

                if not bottomHeapify:
                    break

    def printHeap(self):
        result = []
        for value in self.value_at_position:
            result.append(value)

        print(result)

    def print_heap(self):
        # str_heap = f"{self.getValue(0)}\n"
        str_heap = f"Heap:\n"
        result = []
        height = int(math.log2(len(self.value_at_position) - 1)) + 1

        for i in range(height):
            start = int(math.pow(2, i) - 1)
            offset = int(math.pow(2, i))
            for j in range(offset):
                try:
                    str_heap += f"  ({start + j}, " \
                                f"{self.position_of_vertex[start + j]}, " \
                                f"{self.vertex_at_position[start + j]}, " \
                                f"{self.value_at_position[start + j]})"
                except:
                    str_heap += ""
            str_heap += "\n"
        return str_heap

    def popMin(self):
        """
        removes max value from the heap and returns the name and value of the removed object.
        :return:
        """
        pop_vertex = self.vertex_at_position[0]
        pop_value = self.value_at_position[0]
        self.delete(pop_vertex)
        return pop_vertex, pop_value