Add Grapg/Dijkatra.cpp

Graph/Dijkatra.cpp

+//Include the head file
+#include <iostream>
+
+//Import the namespace
+using namespace std;
+
+//Define some marco variable
+#define MAXNUM 10
+#define MAXSIZE MAXNUM *MAXNUM
+
+//The var we need.
+int VertexNum = 0;              //Vertex number
+int AM[MAXSIZE][MAXSIZE] = {0}; //Adjacency matrix
+int Route[MAXNUM] = {0};        //The path length we walk last time.
+bool S[MAXNUM] = {false};       //Set s, used to determine which is in the set
+
+/*
+This is the adjacency matrix.
+Only for test.
+0 3 4 0 0 0 
+3 0 6 10 0 0
+4 6 0 3 2 0
+0 10 3 0 2 2
+0 0 2 2 0 4
+0 0 0 2 4 0
+*/
+
+//Function we use.
+void DisplayMartix(int D[][MAXSIZE]); //Display the martix
+void DisplaySet(bool S[MAXNUM]);      //Display the set
+
+int main()
+{
+    //Preparation
+    int i; //Common cycle control variables
+
+    //Get the vertex number.
+    cout << "Vertex num:  ";
+    cin >> VertexNum;
+
+    //Get the adjacency matrix.
+    cout << "Adjacency matrix:" << endl;
+    for (i = 0; i < VertexNum - 1; i++)
+    {
+        for (int j = 0; j < VertexNum; j++)
+        {
+            cin >> AM[i][j];
+        }
+    }
+
+    //Show the adjacency martix.
+    DisplayMartix(AM);
+
+    //Start the dijkatra.
+    S[0] = true;                    //Push s1 to the set S.
+    int lasPathLen = 0, lasPos = 0; //Record last path and subscript
+    //Loop all nodes
+    for (int count = 1; count < VertexNum; count++)
+    {
+        //Show the elements in S.
+        DisplaySet(S);
+
+        //Computation path length
+        cout << 'U' << count << "U   ";
+        for (i = 0; i < VertexNum; i++)
+        {
+            if (!S[i])
+            {
+                if (Route[i] == 0 && AM[lasPos][i] != 0)
+                {
+                    Route[i] = AM[lasPos][i] + lasPathLen;
+                }
+                else
+                {
+                    Route[i] = (AM[lasPos][i] + lasPathLen > Route[i]) ? Route[i] : (AM[lasPos][i] + lasPathLen);
+                }
+                cout << Route[i] << ' ';
+            }
+        }
+        cout << endl;
+
+        //Record the min element position.
+        int MIN = -1;
+        //To locate the min element position and value.
+        for (int i = 0; i < VertexNum; i++)
+        {
+            //If not in set
+            if (!S[i])
+            {
+                //If length is not infinite
+                //And the position i in route is alive.
+                if (Route[i] != 0 && (MIN == -1 || MIN > Route[i]))
+                {
+                    lasPos = i;
+                    MIN = Route[i];
+                }
+            }
+        }
+        S[lasPos] = true;
+        lasPathLen = MIN;
+        cout << "To " << lasPos + 1 << " min length " << lasPathLen << endl
+             << endl;
+    }
+}
+
+//Display the martix
+void DisplayMartix(int D[][MAXSIZE])
+{
+    for (int i = 0; i < VertexNum; i++)
+    {
+        for (int j = 0; j < VertexNum; j++)
+        {
+            cout << D[i][j] << '\t';
+        }
+        cout << endl;
+    }
+}
+
+//Display the set
+void DisplaySet(bool S[MAXNUM])
+{
+    //Show the elements in S.
+    cout << "Set   " << '\t';
+    for (int i = 0; i < VertexNum; i++)
+    {
+        if (S[i])
+        {
+            cout << i << ' ';
+        }
+    }
+    cout << endl;
+}
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