Prim's Algorithm.ipynb

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   "source": [
    "## Prim's Algorithm"
   ]
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      "Edge \tWeight\n",
      "0 - 1 \t 2\n",
      "1 - 2 \t 3\n",
      "0 - 3 \t 6\n",
      "1 - 4 \t 5\n"
     ]
    }
   ],
   "source": [
    "class Graph():\n",
    "    def __init__(self, vertices):\n",
    "        self.V = vertices\n",
    "        self.graph = [[0 for column in range(vertices)]\n",
    "                      for row in range(vertices)]\n",
    "        \n",
    "    def printMST(self, parent):\n",
    "        print(\"Edge \\tWeight\")\n",
    "        for i in range(1, self.V):\n",
    "            print(parent[i], \"-\", i, \"\\t\", self.graph[i][parent[i]])\n",
    "            \n",
    "    def minKey(self, key, mstSet):\n",
    "        min = sys.maxsize\n",
    "        for v in range(self.V):\n",
    "            if key[v] < min and mstSet[v] == False:\n",
    "                min = key[v]\n",
    "                min_index = v\n",
    "        return min_index\n",
    "    \n",
    "    def primMST(self):\n",
    "        key = [sys.maxsize] * self.V\n",
    "        parent = [None] * self.V\n",
    "        key[0] = 0\n",
    "        mstSet = [False] * self.V\n",
    "        parent[0] = -1\n",
    "        for cout in range(self.V):\n",
    "            u = self.minKey(key, mstSet)\n",
    "            mstSet[u] = True\n",
    "            for v in range(self.V):\n",
    "                if self.graph[u][v] > 0 and mstSet[v] == False and key[v] > self.graph[u][v]:\n",
    "                    key[v] = self.graph[u][v]\n",
    "                    parent[v] = u\n",
    "                    \n",
    "        self.printMST(parent)\n",
    "        \n",
    "if __name__ == '__main__':\n",
    "    g = Graph(5)\n",
    "    g.graph = [[0, 2, 0, 6, 0],\n",
    "               [2, 0, 3, 8, 5],\n",
    "               [0, 3, 0, 0, 7],\n",
    "               [6, 8, 0, 0, 9],\n",
    "               [0, 5, 7, 9, 0]]\n",
    "    g.primMST()"
   ]
  }
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