dijkstra's algorithm and a* code in c++ code example

Example 1: dijkstra in c++

void dijkstra(int s) {
  priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > pq;
  for (int i=0; i<N; i++) dist[i] = INF;
  dist[s] = 0;
  pq.push(make_pair(0, s));
  while (!pq.empty()) {
    pair<int, int> front = pq.top();
    pq.pop();
    int w = front.first, u = front.second;
    if (w > dist[u]) continue;
    for (int i=0; i<adj[u].size(); i++) {
      pair<int, int> v = adj[u][i];
      if (dist[v.first] > dist[u] + v.second) {
        dist[v.first] = dist[u] + v.second;
        pq.push(make_pair(dist[v.first], v.first));
      }
    }
  }
}

Example 2: Dijkstra’s Algorithm code in C

#include<stdio.h>#include<conio.h>#define INFINITY 9999#define MAX 10 void dijikstra(int G[MAX][MAX], int n, int startnode); void main(){	int G[MAX][MAX], i, j, n, u;	clrscr();	printf("\nEnter the no. of vertices:: ");	scanf("%d", &n);	printf("\nEnter the adjacency matrix::\n");	for(i=0;i < n;i++)		for(j=0;j < n;j++)			scanf("%d", &G[i][j]);	printf("\nEnter the starting node:: ");	scanf("%d", &u);	dijikstra(G,n,u);	getch();} void dijikstra(int G[MAX][MAX], int n, int startnode){	int cost[MAX][MAX], distance[MAX], pred[MAX];	int visited[MAX], count, mindistance, nextnode, i,j;	for(i=0;i < n;i++)		for(j=0;j < n;j++)			if(G[i][j]==0)				cost[i][j]=INFINITY;			else				cost[i][j]=G[i][j];		for(i=0;i< n;i++)	{		distance[i]=cost[startnode][i];		pred[i]=startnode;		visited[i]=0;	}	distance[startnode]=0;	visited[startnode]=1;	count=1;	while(count < n-1){		mindistance=INFINITY;		for(i=0;i < n;i++)			if(distance[i] < mindistance&&!visited[i])			{				mindistance=distance[i];				nextnode=i;			}		visited[nextnode]=1;		for(i=0;i < n;i++)			if(!visited[i])				if(mindistance+cost[nextnode][i] < distance[i])				{					distance[i]=mindistance+cost[nextnode][i];					pred[i]=nextnode;				}			count++;	} 	for(i=0;i < n;i++)		if(i!=startnode)		{			printf("\nDistance of %d = %d", i, distance[i]);			printf("\nPath = %d", i);			j=i;			do			{				j=pred[j];				printf(" <-%d", j);			}			while(j!=startnode);		}}