Лабораторная работа №6 / MDLab6-MaxFlow

#include <stdio.h>
#include <alloc.h>
#include <conio.h>

struct List{
	int v;
   int w;
   int f;
   struct List *next;
};

struct Graph{
	int p;
   int c;
   struct List *first;
   struct List *last;
}*G;

int N;

int  BFS();
void MinCut();
void MaxFlow();
void Menu();
void ListAdj();
void FreeList();

void main()
{
	Menu();
}

void MaxFlow()
{
	int u,v,addtoflow,maxflow=0;
   struct List *c;
   while(addtoflow=BFS()){
   	v=N-1;
      u=G[v].p;
     	while(u!=-1){
      	c=G[u].first;
         while(c->v!=v)
         	c=c->next;
         c->f+=addtoflow;
         v=u;
         u=G[u].p;
      }
   }
   c=G[0].first;
   while(c!=G[0].last){
   	maxflow+=c->f;
      c=c->next;
   }
   printf("Maximum flow is %d",maxflow);
   MinCut();
}

void MinCut()
{
  /* int i;
   struct List *c;
   printf("\nMinumum cut: ");
   for(i=0;i<N;i++)
   	if(!G[i].c){
      	c=G[i].first;
         while(c!=G[i].last){
         	if(G[c->v].c)
            	printf("%d-%d ",i+1,c->v+1);
            c=c->next;
         }
      } */	
}


int BFS()
{
	int i,mw=0,v,u,qbeg=0,qend,*Q=(int *)malloc(N*sizeof(int ));
   struct List *c;
   for(i=0;i<N;i++){
   	G[i].c=1;
      G[i].p=-1;
   }
   Q[qbeg]=0;
   qend=1;
   while(qbeg!=qend){
   	u=Q[qbeg++];
      c=G[u].first;
      while(c!=G[u].last){
      	if(G[c->v].c && c->w!=c->f){
         	G[c->v].c=0;
            G[c->v].p=u;
            Q[qend++]=c->v;
         }
      	c=c->next;
      }
   }
   v=N-1;
   u=G[v].p;
   while(u!=-1){
   	c=G[u].first;
      while(c->v!=v)
      	c=c->next;
      if(!mw || mw>c->w-c->f)
      	mw=c->w-c->f;
      v=u;
      u=G[u].p;
   }
   return mw;
}

void Menu()
{
   int i;
	char ch;
	clrscr();
	printf("1.To enter the graph\n");
	printf("2.Maximum flow by Ford-Fulkerson's algorithm\n");
	printf("3.Exit\n");
	do
		ch=getch();
	while(ch<'1' || ch>'3');
	clrscr();
	switch (ch)
	{
		case '1': ListAdj();break;
		case '2': MaxFlow();getch();break;
		case '3': FreeList();return;
	}
	Menu();
}

void ListAdj()
{
	int i,v,w;
	struct List *c;
   if(G)
		FreeList();
   printf("Enter number of vertexes of graph: ");
   scanf("%d",&N);
   G=(struct Graph *)malloc(N*sizeof(struct Graph));
	printf("\n");
	for(i=0;i<N;i++){
		printf("%d->",i+1);
      G[i].first=(struct List*)malloc(sizeof(struct List));
      G[i].last=G[i].first;
      G[i].last->next=NULL;
      G[i].last->v=-1;
      scanf("%d",&v);
		while(v){
			scanf("%d",&w);
         G[i].last->v=v-1;
         G[i].last->w=w;
         G[i].last->f=0;
         G[i].last->next=(struct List*)malloc(sizeof(struct List));
         G[i].last=G[i].last->next;
         G[i].last->next=NULL;
      	G[i].last->v=-1;
	 		scanf("%d",&v);
		}
	}
}

void FreeList()
{
	struct List *c,*t;
	while(N--){
		c=G[N].first;
		while(c!=G[N].last){
			t=c->next;
			free(c);
			c=t;
		}
	}
   free(G);
}