1 #include <stdio.h> 2 #include<iostream> 3 using namespace std; 4 struct home 5 { 6 int a; 7 int b; 8 int dis; 9 int _Construct; 10 }v[5008]; 11 int father[200]; 12 int sum=0; 13 int cmp(const void *a,const void *b) 14 { 15 struct home *c,*d; 16 c=(struct home *)a; 17 d=(struct home *)b; 18 return c->dis-d->dis; 19 } 20 21 int findx(int x) 22 { 23 while(x!=father[x]) 24 x=father[x]; 25 return x; 26 } 27 void merge(home x) 28 { 29 int fx=findx(x.a),fy=findx(x.b); 30 if(fx!=fy) 31 { 32 father[fx]=fy; 33 if(x._Construct==0) 34 sum+=x.dis; 35 } 36 37 } 38 int main() 39 { 40 #ifdef inandout 41 freopen("C:\Users\lx\Desktop\1.in","r",stdin); 42 #endif 43 44 int T; 45 while(scanf("%d",&T),T!=0) 46 { 47 int i,j; 48 int test=0; 49 int n=T*(T-1)/2; 50 for(i=1;i<=n;i++) 51 scanf("%d%d%d%d",&v[i].a,&v[i].b,&v[i].dis,&v[i]._Construct); 52 for(i=1;i<=T;i++) 53 father[i]=i; 54 qsort(v,n+1,sizeof(v[0]),cmp); 55 for(i=1;i<=n;i++) 56 { 57 if(v[i]._Construct==1) 58 merge(v[i]); 59 } 60 for(i=1;i<=n;i++) 61 { 62 merge(v[i]); 63 } 64 for(i=1;i<=T;i++) 65 { 66 if(i==father[i]) 67 test++; 68 } 69 if(test>1) 70 printf("? "); 71 else 72 printf("%d ",sum); 73 sum=0; 74 } 75 76 return 0; 77 }
路径压缩版findx
int findx(int x) { if(x!=father[x]) x=findx(father[x]); else return x; } int findfast(int x) { if(x!=father[x]) father[x]=findx(father[x]); else return father[x]; }
例HDU1181
#define DeBUG #include <iostream> #include <cstdio> #include <cstring> #include <cmath> #include <cstdlib> #include <algorithm> #include <vector> #include <stack> #include <queue> #include <string> #include <set> #include <sstream> #include <map> #include <bitset> using namespace std ; #define zero {0} #define INF 2000000000 #define EPS 1e-6 typedef long long LL; const double PI = acos(-1.0); inline int sgn(double x){return fabs(x) < EPS ? 0 :(x < 0 ? -1 : 1);} int father[1000]; int findx(int x) { if(x!=father[x]) x=findx(father[x]); else return x; } int findfast(int x) { if(x!=father[x]) father[x]=findx(father[x]); else return father[x]; } void merge(int a,int b) { int fx=findfast(a); int fy=findfast(b); if(fx!=fy) { father[fy]=fx; } } void init() { for(int i=0;i<1000;i++) father[i]=i; } int main() { #ifdef DeBUGs freopen("C:\Users\Sky\Desktop\1.in","r",stdin); #endif char s[1000]; int t=0; init(); while(scanf("%s", s)+1) { int len=strlen(s); merge(s[0],s[len-1]); if(s[0]=='0') { if(findx('m')=='b') printf("Yes. "); else printf("No. "); init(); } } return 0; }