C + + path advanced codevs1242 (layout)

1242 Layout 

2005 Usaco

time limit: 1 sspace limit: 128000 KBtitle level: Golden Gold

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Title Description Description

When waiting in line for feeding, cows like to stand close to their friends. FJ have n (2<=n<=1000) cows, numbered from 1 to N, standing along a straight line waiting to be fed. The order of the cows in the queue is the same as their number. Because cows are quite slim, there may be two or more cows standing in the same position. Even if we imagine cows standing on a single axis, it allows two or more cows to have the same horizontal axis.

Some cows are fond of each other, and they hope that the distance between the two is no more than a given number L. On the other hand, some cows are very disgusted with each other, and they hope that the distance between the two is not less than a given number d. This article gives a description of the good graces between two cows, and gives a description of the dislike of the two cows by the MD bar. (1<=ml,md<=10000,1<=l,d<=1000000)

Your job is: if there are no scenarios to meet the requirements, output-1; If number 1th cows and n

The distance between cows can be arbitrarily large, output-2; otherwise, the maximum distance between the number 1th cows and the n cows may be calculated if all the requirements are met.

Enter a description Input Description Line 1:three space-separated integers:n, ML, and MD.

Lines 2..ml+1:each Line contains three space-separated positive integers:a, B, and D, with 1 <= A < B <= N. Cow s A and B must is at the most D (1 <= D <= 1,000,000) apart.

Lines Ml+2..ml+md+1:each Line contains three space-separated positive integers:a, B, and D, with 1 <= A < B <= N. Cows A and B must is at least D (1 <= D <= 1,000,000) apart. Output description Output Description Line 1: A single integer. If no line-up is possible, output-1. If cows 1 and N can be arbitrarily far apart, output-2. Otherwise output The greatest possible distance between cows 1 and N. Sample input Sample Input

4 2 1
1 3 10
2 4 20
2 3 3

Sample output Sample Output

27

Data range and Tips Data Size & Hint Solvingdifferential!!! (I'm not very good at learning ... )

1#include <cstdio>2#include <queue>3#include <iostream>4#include <algorithm>5 #defineMAXN 10000+106 #defineINF 0x7fffffff7 8 using namespacestd;9 Ten intHEAD[MAXN],CNT,DIS[MAXN],VIS[MAXN],INQ[MAXN],N,ML,MD; One  A structSS -    { -         intTo,next,edge; the}e[100000<<1]; -     - voidInsertintUintVintedge) -    { +e[++cnt].to=v,e[cnt].next=head[u],e[cnt].edge=edge,head[u]=CNT; -    }    +  A intSPFA () at     { -queue<int>que;  -dis[1]=0;  -vis[1]=1;  -inq[1]++; -Que.push (1); in       intflag=0;  -        while(!que.empty ()) to          { +              intNow=que.front (); Que.pop (); vis[now]=0; -               for(intI=head[now];i;i=e[i].next) the                  { *                     if(dis[e[i].to]>dis[now]+E[i].edge) $                        {Panax Notoginsengdis[e[i].to]=dis[now]+E[i].edge; -                          if(!vis[e[i].to]) the                          { +vis[e[i].to]=1; Que.push (e[i].to); Ainq[e[i].to]++; the                            if(inq[e[i].to]>n)return-1;  +                          }  -                       } $                           $                  } -          } -       returnDis[n];  the     } - Wuyi intMain () the    { -scanf"%d%d%d",&n,&ml,&MD); Wu          for(intI=1; i<=ml;i++) -             { About                 intx, y, z $scanf"%d%d%d",&x,&y,&z); - Insert (x, y, z); -             } -         for(intI=1; i<=md;i++) A          { +            intx, y, z thescanf"%d%d%d",&x,&y,&z); -Insert (y,x,-z);  $          }  the      for(intI=1; i<=n;i++) dis[i]=INF;  the     intans=SPFA ();  the     if(Ans==inf) cout<<-2<<Endl; the          Elsecout<<ans<<Endl;  -     return 0;  in}

C + + path advanced codevs1242 (layout)