Answers for "bellman ford algorithm cp algorithm"

C++
1

bellman ford algorithm

//It is an algorithm to detect negative cycle in a graph as well as can we used to find the shortest distance from source

#include<bits/stdc++.h>
using namespace std;
struct node
{
    int u,v,wt;
    node(int first,int second ,int weight)
    {
        u=first;
        v=second;
        wt=weight;
    }
};
int main()
{
   int vertex,edges;
   cout<<"ENTER THE NUMBER OF VERTEX AND EDGES:"<<endl;
   cin>>vertex>>edges;
   vector<node>adj;
   cout<<"ENTER THE LINKS:"<<endl;
   int a,b,w;
   for(int i=0;i<edges;i++)
   {
       cin>>a>>b>>w;
       adj.push_back(node(a,b,w));
   }
   int src;
   cout<<"ENTER THE SOURCE"<<endl;
   cin>>src;
   int large=100000;
   vector<int>dist(vertex,large);
   dist[src]=0;
   for(int i=1;i<=vertex-1;i++)
   {
       for(auto it:adj)
       {
           if(dist[it.u]+it.wt<dist[it.v])
           {
               dist[it.v]=dist[it.u]+it.wt;
           }
       }
   }
   int flag=0;
   for(auto it:adj)
       {
           if(dist[it.u]+it.wt<dist[it.v])
           {
               cout<<"NEGATIVE CYCLE DETECTED:"<<endl;
               flag=1;
               break;
           }
       }
       if(!flag)
       {
           for(int i=0;i<vertex;i++)
           {
               cout<<i<<" "<<dist[i]<<endl;
           }
       }
       return 0;
}
Posted by: Guest on September-08-2021
2

bellman ford algorithm cp algorithm

struct edge
{
    int a, b, cost;
};

int n, m, v;
vector<edge> e;
const int INF = 1000000000;

void solve()
{
    vector<int> d (n, INF);
    d[v] = 0;
    for (int i=0; i<n-1; ++i)
        for (int j=0; j<m; ++j)
            if (d[e[j].a] < INF)
                d[e[j].b] = min (d[e[j].b], d[e[j].a] + e[j].cost);
    // display d, for example, on the screen
}
Posted by: Guest on June-18-2020
1

bellman ford algorithm

#include <vector>
#include <iostream>
using namespace std;

#define INF 99999;

struct Edge {
	int u, v, w;
};

int V; 							// Number of verticies.
vector<vector<Edge>> adjList;	// Adjacency list.
vector<vector<int>> adjMatrix;	// Adjacency matrix.

// With adjacency list.
int* shortestPath(int src) {
	int dist[V];
  	for (int u = 0; u < V; ++u)
      dist[u] = INF;
  	dist[src] = 0;

	for (int i = 0; i < V - 1; ++i)
		for (int u = 0; u < V; ++u)
			for (Edge e : adjList[u])
				if (dist[e.u] + e.w < dist[e.v])
          			dist[e.v] = dist[e.u] + e.w;
  
  	for (int u = 0; u < V; ++u)
		for (Edge e : adjList[u])
        	if (dist[e.u] + e.w < dist[e.v])
            	throw std::runtime_error("negative loop detected")
    
    // contains the shortest dist between src and each vertex.
  	return dist;
}

// With adjacency matrix.
int* shortestPath(int src) {
	int dist[V];
  	for (int u = 0; u < V; ++u)
      dist[u] = INF;
  	dist[src] = 0;

	for (int i = 0; i < V - 1; ++i)
		for (int u = 0; u < V; ++u)
			for (int v = 0; v < V; ++v)
				if (dist[u] + adjMatrix[u][v] < dist[v])
          			dist[v] = dist[u] + adjMatrix[u][v];
  
  	for (int u = 0; u < V; ++u)
		for (int v = 0; v < V; ++v)
        	if (dist[u] + adjMatrix[u][v] < dist[v])
            	throw std::runtime_error("negative loop detected")
    
    // contains the shortest dist between src and each vertex.
  	return dist;
}
Posted by: Guest on April-26-2021

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