UVa 10596 moring Walk "Euler circuit"

Test instructions: Give n points, M road, ask whether can go through M road.

When I do it = = nimbly with and check the set made, WA a pitch-and then WA a few hair-(and also to judge the connectivity of AH)

Search the Puzzle = = found to be this:

Because it is only required to walk all the way, that is, just to finish the road that has been given, and there is no requirement that all the points along the way,

For example, given the way to have these

0 1

1 2

2 3

3 0

4 4

Then the road is formed, walking round the blue line in the picture, that is, to walk all the way,

and 4 is an outlier, and it does not constitute a road, so it does not need to be taken care of.

The IF (d[i]!=0) in the code is to determine if the point is an outlier.

1#include <iostream>2#include <cstdio>3#include <cstring>4#include <algorithm>5 using namespacestd;6 intd[10010],pre[10010];7 intFindintRoot) {returnRoot = = Pre[root]? Root:pre[root] =find (Pre[root]);}8 voidUnionroot (intXinty)9 {Ten     introot1=find (x); One     intRoot2=find (y); A     if(Root1!=root2) pre[root1]=Root2; - } -  the intMain () - { -     intm,n,u,v,i; -      while(SCANF ("%d%d", &n,&m)! =EOF) +     { -             intflag=1; +memset (D,0,sizeof(d)); Amemset (PRE,0,sizeof(pre)); at          for(i=0; i<=10010; i++) -pre[i]=i; -          for(i=1; i<=m;i++) -         { -scanf"%d%d",&u,&v); -d[u]++; ind[v]++; - Unionroot (u,v); to         } +          -         intRoot=find (0); the          *         if(m==0|| n==0) flag=0;//n=0 can not form a circuit, m=0 time can not $         Panax Notoginseng          for(i=0; i<n;i++){      -                 if(d[i]!=0){//determine if this point is an isolated point the                     if(Find (i)!=root| | d[i]%2!=0){//determine if the point is on the same unicom block, and whether the store has an even number of degrees +flag=0; A                      Break; the                   } +                 }  -         } $          $         if(flag) -printf"possible\n"); -         Else theprintf"Not possible\n");  -     }Wuyi     return 0; the}

View Code

She just wants to go all the way, she doesn't want to go 4

Go---go---

UVa 10596 moring Walk "Euler circuit"