mirror of
https://github.com/cc65/cc65.git
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370 lines
8.0 KiB
C
370 lines
8.0 KiB
C
/*
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!!DESCRIPTION!! Dijkstras Algorithm
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!!ORIGIN!! testsuite
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!!LICENCE!! Public Domain
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!!AUTHOR!! Groepaz/Hitmen
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#ifndef NULL
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#define NULL ((void*)0)
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#endif
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#define DIJKSTRA_INFINITY (0xffff)
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#define DIJKSTRA_FLAG_UNVISITED (0x0)
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/*
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#define DIJKSTRA_FLAG_OPEN (0x1)
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*/
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#define DIJKSTRA_FLAG_CLOSED (0x2)
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typedef struct _DIJKSTRA_EDGE {
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struct _DIJKSTRA_NODE *NEXTNODE;
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unsigned short DISTANCE;
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} DIJKSTRA_EDGE;
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typedef struct _DIJKSTRA_NODE {
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DIJKSTRA_EDGE *EDGES;
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unsigned char TAG;
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unsigned char FLAG;
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unsigned short MINDIST;
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struct _DIJKSTRA_NODE *PREVIOUS;
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} DIJKSTRA_NODE;
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/* init with graph, startnode, working-array */
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void Dijkstra_Init(const DIJKSTRA_NODE *graph,DIJKSTRA_NODE *start,DIJKSTRA_NODE *nodes);
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/* call main algo with working-array */
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void Dijkstra_Search(DIJKSTRA_NODE *nodes);
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/* print path, call with working-array, endnode */
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void Dijkstra_Path(DIJKSTRA_NODE *nodes,DIJKSTRA_NODE *end);
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/* print table, call with working-array, current node */
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void Dijkstra_Table(DIJKSTRA_NODE *nodes,DIJKSTRA_NODE *current);
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/* internally used routines */
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unsigned short Dijkstra_Distance(DIJKSTRA_NODE *currnode,DIJKSTRA_NODE *nextnode);
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void Dijkstra_Relax(DIJKSTRA_NODE *currnode,DIJKSTRA_NODE *nextnode);
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DIJKSTRA_NODE *Dijkstra_NextCheapest(DIJKSTRA_NODE *graph);
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unsigned short Dijkstra_CountUnvisited(DIJKSTRA_NODE *graph);
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/* define to get printed info as the algorithm proceeds */
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#define DIJKSTRA_PRINTDEBUG
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/* the working array */
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DIJKSTRA_NODE mynodes[0x10];
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/* test-network data (mypoints and myedges) */
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const DIJKSTRA_EDGE myedges_A[]={
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{&mynodes[1],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_B[]={
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{&mynodes[0],1},
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{&mynodes[2],2},
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{&mynodes[3],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_C[]={
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{&mynodes[1],2},
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{&mynodes[5],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_D[]={
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{&mynodes[1],1},
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{&mynodes[4],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_E[]={
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{&mynodes[6],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_F[]={
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{&mynodes[7],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_G[]={
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{&mynodes[8],1},
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{&mynodes[7],4},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_H[]={
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{&mynodes[9],1},
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{&mynodes[6],4},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_I[]={
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{&mynodes[10],5},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_J[]={
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{&mynodes[10],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_K[]={
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{&mynodes[11],1},
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{NULL}
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};
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const DIJKSTRA_EDGE myedges_L[]={
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{&mynodes[10],1},
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{NULL}
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};
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const DIJKSTRA_NODE mypoints[]={
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{(DIJKSTRA_EDGE *)&myedges_A[0],'A'},
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{(DIJKSTRA_EDGE *)&myedges_B[0],'B'},
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{(DIJKSTRA_EDGE *)&myedges_C[0],'C'},
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{(DIJKSTRA_EDGE *)&myedges_D[0],'D'},
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{(DIJKSTRA_EDGE *)&myedges_E[0],'E'},
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{(DIJKSTRA_EDGE *)&myedges_F[0],'F'},
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{(DIJKSTRA_EDGE *)&myedges_G[0],'G'},
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{(DIJKSTRA_EDGE *)&myedges_H[0],'H'},
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{(DIJKSTRA_EDGE *)&myedges_I[0],'I'},
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{(DIJKSTRA_EDGE *)&myedges_J[0],'J'},
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{(DIJKSTRA_EDGE *)&myedges_K[0],'K'},
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{(DIJKSTRA_EDGE *)&myedges_L[0],'L'},
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{NULL}
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};
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/*
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* initialize working-array
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*/
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void Dijkstra_Init(const DIJKSTRA_NODE *graph,DIJKSTRA_NODE *start,DIJKSTRA_NODE *nodes) {
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while(graph->EDGES!=NULL) {
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nodes->EDGES=graph->EDGES;
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nodes->TAG=graph->TAG;
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nodes->FLAG=DIJKSTRA_FLAG_UNVISITED;
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nodes->MINDIST=DIJKSTRA_INFINITY;
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nodes->PREVIOUS=NULL;
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graph++;nodes++;
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}
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/*
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start->FLAG=DIJKSTRA_FLAG_OPEN;
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start->PREVIOUS=NULL;
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*/
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start->MINDIST=0;
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}
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/*
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* compute the distance between two Nodes in the Graph
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*/
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unsigned short Dijkstra_Distance(DIJKSTRA_NODE *currnode,DIJKSTRA_NODE *nextnode){
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DIJKSTRA_EDGE *edge;
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edge=currnode->EDGES;
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while(edge!=NULL) {
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if(edge->NEXTNODE == nextnode){
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return(edge->DISTANCE);
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}
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edge++;
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}
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return(DIJKSTRA_INFINITY);
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}
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/*
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* 'relax' one node against another
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*/
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void Dijkstra_Relax(DIJKSTRA_NODE *currnode,DIJKSTRA_NODE *nextnode){
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unsigned short newdist;
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#ifdef DIJKSTRA_PRINTDEBUG
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printf("relax >%c< to >%c<\n",currnode->TAG,nextnode->TAG);
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#endif
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newdist=currnode->MINDIST+Dijkstra_Distance(currnode,nextnode);
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if((nextnode->MINDIST)>(newdist)){
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nextnode->MINDIST=newdist;
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nextnode->PREVIOUS=currnode;
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}
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}
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/*
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* find the yet unprocessed Node with the currently
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* smallest estimated MINDIST
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*/
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DIJKSTRA_NODE *Dijkstra_NextCheapest(DIJKSTRA_NODE *graph){
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unsigned short mindist;
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DIJKSTRA_NODE *node;
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node=NULL;
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mindist=DIJKSTRA_INFINITY;
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while(graph->EDGES!=NULL) {
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if(graph->FLAG!=DIJKSTRA_FLAG_CLOSED){
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if(!(mindist<graph->MINDIST)){
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mindist=graph->MINDIST;
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node=graph;
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}
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}
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graph++;
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}
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#ifdef DIJKSTRA_PRINTDEBUG
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if(node!=NULL) printf("next cheapest Node: >%c<\n",node->TAG);
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#endif
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return(node);
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}
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/*
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* count number of Nodes that are left for processing
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*/
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unsigned short Dijkstra_CountUnvisited(DIJKSTRA_NODE *graph){
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unsigned short num;
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num=0;
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while(graph->EDGES!=NULL) {
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if(graph->FLAG!=DIJKSTRA_FLAG_CLOSED){
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num++;
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}
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graph++;
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}
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return(num);
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}
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/*
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* Dijkstra-Algorithmus main processing
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*/
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void Dijkstra_Search(DIJKSTRA_NODE *graph){
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DIJKSTRA_NODE *currnode,*nextnode;
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DIJKSTRA_EDGE *edge;
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currnode=graph;
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while(Dijkstra_CountUnvisited(graph)>0){
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edge=currnode->EDGES;
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while(edge->NEXTNODE!=NULL){
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nextnode=edge->NEXTNODE;
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if(nextnode->FLAG!=DIJKSTRA_FLAG_CLOSED){
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/*
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nextnode->FLAG=DIJKSTRA_FLAG_OPEN;
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*/
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Dijkstra_Relax(currnode,nextnode);
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#ifdef DIJKSTRA_PRINTDEBUG
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Dijkstra_Table(graph,currnode);
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#endif
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}
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edge++;
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}
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currnode=Dijkstra_NextCheapest(graph);
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currnode->FLAG=DIJKSTRA_FLAG_CLOSED;
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}
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}
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/*
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* print the Path from start Node to one other Node
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*/
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void Dijkstra_Path(DIJKSTRA_NODE *graph,DIJKSTRA_NODE *end){
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DIJKSTRA_NODE *currnode,*nextnode;
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printf("Path from >%c< to >%c< : ",end->TAG,graph->TAG);
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currnode=end;
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while(currnode->PREVIOUS!=NULL){
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printf(">%c< ",currnode->TAG);
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currnode=currnode->PREVIOUS;
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}
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printf(">%c<\n",currnode->TAG);
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}
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/*
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* print working-array as a table
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*/
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void Dijkstra_Table(DIJKSTRA_NODE *graph,DIJKSTRA_NODE *current){
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DIJKSTRA_NODE *g;
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printf("----------------------\n");
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printf("Node |");
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g=graph;while(g->EDGES!=NULL) {
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printf("-->%c<-|",g->TAG);
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g++;
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}
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printf("\n");
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printf("MinDist |");
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g=graph;while(g->EDGES!=NULL) {
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printf(" %5u|",g->MINDIST);
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g++;
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}
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printf("\n");
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printf("Flag |");
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g=graph;while(g->EDGES!=NULL) {
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switch(g->FLAG){
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/*
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case DIJKSTRA_FLAG_OPEN:
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printf("opened|");
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break;
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*/
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case DIJKSTRA_FLAG_CLOSED:
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printf("closed|");
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break;
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default:
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if(g->MINDIST!=DIJKSTRA_INFINITY){
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printf("opened|");
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} else {
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printf("------|");
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}
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break;
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}
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g++;
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}
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printf("\n");
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printf("Previous|");
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g=graph;while(g->EDGES!=NULL) {
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if(g->PREVIOUS==NULL)
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printf("------|");
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else
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printf(" (%c) |",g->PREVIOUS->TAG);
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g++;
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}
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printf("\n");
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printf("----------------------\n");
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}
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int main(void)
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{
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/* init with graph, startnode, working-array */
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Dijkstra_Init(&mypoints[0],&mynodes[0],&mynodes[0]);
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/* call main algo with working-array */
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Dijkstra_Search(&mynodes[0]);
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/* print table, call with working-array, endnode */
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Dijkstra_Table(&mynodes[0],&mynodes[11]);
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/* print path, call with working-array, endnode */
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Dijkstra_Path(&mynodes[0],&mynodes[11]);
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return 0;
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}
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