POJ 3169 Layout (differential constraint system)

POJ 3169 Layout (differential constraint system)

Address: POJ 3169

Very simple difference constraint .. The formula is obvious. When the maximum value is input, it is a-B <= c, and the minimum value is a-B> = c. Then, calculate the shortest path based on the formula.

The Code is as follows:

#include 
 
  #include 
  
   #include 
   
    #include 
    
     #include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         #include 
          
           #include using namespace std;const int INF=0x3f3f3f3f;int d[2000], head[2000], cnt, source, sink, aa[2000];struct node{ int u, v, w, next;} edge[1000000];void add(int u, int v, int w){ edge[cnt].u=u; edge[cnt].v=v; edge[cnt].w=w; edge[cnt].next=head[u]; head[u]=cnt++;}int berman(int n){ //memset(vis,0,sizeof(vis)); int i, j, flag; memset(d,INF,sizeof(d)); d[1]=0; for(i=1;i<=n;i++) { flag=0; for(j=0;j
           
            d[edge[j].u]+edge[j].w) { d[edge[j].v]=d[edge[j].u]+edge[j].w; flag=1; } } if(!flag) break; } for(i=0;i
            
             d[edge[i].u]+edge[i].w) { return 0; } } return 1;}int main(){ int n, ml, md, a, b, c, i, j, x; scanf("%d%d%d",&n,&ml,&md); memset(head,-1,sizeof(head)); cnt=0; while(ml--) { scanf("%d%d%d",&a,&b,&c); add(a,b,c); //add(b,a,c); } while(md--) { scanf("%d%d%d",&a,&b,&c); add(b,a,-c); //add(a,b,-c); } x=berman(n); if(!x) printf("-1\n"); else { if(d[n]==INF) printf("-2\n"); else printf("%d\n",d[n]); } return 0;}