4.1）download source code： https://github.com/pacosonTang/dataStructure-algorithmAnalysis/tree/master/chapter9/p224_unweighted_shortest_path 4.2）source code at a glance (for full code, please download source code following the given link above)：
#include "unweightedTable.h"// allocate the memory for every element in unweighted table
UnweightedTable makeEmptyUnweightedTable()
{UnweightedTable element;element = (UnweightedTable)malloc(sizeof(struct UnweightedTable));if(!element){Error("out of space ,from func makeEmptyUnweightedTable");return NULL;} element->known = 0; // 1 refers to accessed , also 0 refers to not accessedelement->distance = MaxInt;element->path = -1; // index starts from 0return element;
}//allocate the memory for initializing unweighted table
UnweightedTable *initUnweightedTable(int size)
{ UnweightedTable* table;int i;table = (UnweightedTable*)malloc(sizeof(UnweightedTable) * size);if(!table){Error("out of space ,from func initUnweightedTable");return NULL;}for(i = 0; i < size; i++){table[i] = makeEmptyUnweightedTable(); if(!table[i])return NULL;}return table;
} //computing the unweighted shortest path between the vertex under initIndex and other vertexsvoid unweighted_shortest_path(AdjTable* adj, int size, int startVertex, Queue queue)
{ int adjVertex; UnweightedTable* table;ElementType vertex; AdjTable temp; table = initUnweightedTable(size); enQueue(queue, startVertex-1); //if let start vertex equals to v3, then initIndex=3 and let index=2 enter the queue table[startVertex-1]->distance = 0;// update the distance table[startVertex-1]->path = 0;// update the path of starting vertexwhile(!isEmpty(queue)){vertex = deQueue(queue); // if the queue is not empty, conducting departing queue table[vertex]->known = 1; // update the vertex as accessed, also responding known 1temp = adj[vertex]->next;while(temp){adjVertex = temp->index; // let each adjVertex adjacent to vertex enter the queueif(table[adjVertex]->path == -1) // key that judge whether corresponding element's path equals to -1 ,-1 means the element has never entered the queue{enQueue(queue, adjVertex); table[adjVertex]->distance = table[vertex]->distance + 1;// update the distance table[adjVertex]->path = vertex; //update the path of adjVertex, also responding path evaluated as vertex}temp = temp->next; } }disposeQueue(queue);//print unweighted tableprintUnweightedtable(table, size, startVertex);printf("\n\t");
} //print unweighted tablevoid printUnweightedtable(UnweightedTable* table, int size, int startVertex)
{int i;int path;char *str[4] = {"vertex","known","distance","path"};printf("\n\t unweighted shortest path table are as follows:\n"); printf("\n\t %6s%6s%9s%5s", str[0], str[1], str[2], str[3]); for(i=0; i<size; i++){ if(i != startVertex-1) printf("\n\t %-3d %3d %5d v%-3d ", i+1, table[i]->known, table[i]->distance, table[i]->path+1);elseprintf("\n\t *%-3d %3d %5d %-3d ", i+1, table[i]->known, table[i]->distance, 0);}
}int main()
{ AdjTable* adj; Queue queue;int size = 7;int i;int j;int column = 4;int startVertex;int adjTable[7][4] = {{2, 4, 0, 0},{4, 5, 0, 0},{1, 6, 0, 0},{3, 5, 6, 7},{7, 0, 0, 0},{0, 0, 0, 0},{6, 0, 0, 0}};printf("\n\n\t ====== test for topological sorting with adjoining table ======\n");adj = initAdjTable(size); queue = initQueue(size);printf("\n\n\t ====== the initial adjoining table is as follows:======\n");for(i = 0; i < size; i++)for(j = 0; j < column; j++) if(adjTable[i][j]) insertAdj(adj, adjTable[i][j]-1, i); // insertAdj the adjoining table over printAdjTable(adj, size);// finding the unweighted shortest path starts // void unweighted_shortest_path(AdjTable* adj, int size, int initIndex, Queue queue)startVertex = 3; // we set the vertex3 as the start vertex (but you know, whose index in array is 2)unweighted_shortest_path(adj, size, startVertex, queue);return0;
}
