ford fulkerson.cpp

#include <iostream>
#include <string.h>
#include <queue>
using namespace std;
bool bfs(int rGraph[][6], int s, int t, int parent[])
{
    bool visited[6];
    memset(visited, 0, sizeof(visited));
    queue <int> q;
    q.push(s);
    visited[s] = true;
    parent[s] = -1;
 
    while (!q.empty())
    {
        int u = q.front();
        q.pop();
        for (int v = 0; v < 6; v++)
        {
            if (visited[v] == false && rGraph[u][v] > 0)
            {
                q.push(v);
                parent[v] = u;
                visited[v] = true;
            }
        }
    }
    return (visited[t] == true);
}
 
int fordFulkerson(int graph[6][6], int s, int t)
{
    int u, v;
    int rGraph[6][6];  
    for (u = 0; u < 6; u++)
    {
        for (v = 0; v < 6; v++)
        {
            rGraph[u][v] = graph[u][v];
        }
    }
    int parent[6];
    int max_flow = 0;
    while (bfs(rGraph, s, t, parent))
    {
        int path_flow = INT_MAX;
        for (v = t; v != s; v = parent[v])
        {
            u = parent[v];
            path_flow = min(path_flow, rGraph[u][v]);
        }
        for (v = t; v != s; v = parent[v])
        {
            u = parent[v];
            rGraph[u][v] -= path_flow;
            rGraph[v][u] += path_flow;
        }
        max_flow += path_flow;
    }
    return max_flow;
}
int main()
{
    int graph[6][6] = { {0, 16, 13, 0, 0, 0},
                        {0, 0, 10, 12, 0, 0},
                        {0, 4, 0, 0, 14, 0},
                        {0, 0, 9, 0, 0, 20},
                        {0, 0, 0, 7, 0, 4},
                        {0, 0, 0, 0, 0, 0}
                      }; 
    cout << "The maximum possible flow is " << fordFulkerson(graph, 0, 5);
    getch();
}