poj 2404 Jogging Trails
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1 #include <bits/stdc++.h> 2 using namespace std; 3 inline int ra() 4 { 5 int x=0,f=1; char ch=getchar(); 6 while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();} 7 while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();} 8 return x*f; 9 } 10 int n,m,ed,tot,top; 11 int d[20],q[20]; 12 int f[32768],dis[20][20]; 13 int bin[20]; 14 void floyd() 15 { 16 for (int k=1; k<=n; k++) 17 for (int i=1; i<=n; i++) 18 for (int j=1; j<=n; j++) 19 dis[i][j]=min(dis[i][j],dis[i][k]+dis[k][j]); 20 } 21 void dp() 22 { 23 memset(f,127/3,sizeof(f)); 24 f[0]=0; 25 for (int i=0; i<ed; i++) 26 { 27 int x=1; 28 while (bin[x-1]&i) x++; 29 for (int y=x+1; y<=top; y++) 30 if ((i&bin[y-1])==0) 31 f[i|bin[y-1]|bin[x-1]]=min(f[i|bin[y-1]|bin[x-1]],f[i]+dis[q[x]][q[y]]); 32 } 33 } 34 int main(int argc, char const *argv[]) 35 { 36 bin[0]=1; for (int i=1; i<=20; i++) bin[i]=bin[i-1]<<1; 37 while (1) 38 { 39 top=tot=0; 40 memset(dis,127/3,sizeof(dis)); 41 memset(d,0,sizeof(d)); 42 n=ra(); if (!n) break; m=ra(); 43 for (int i=1; i<=m; i++) 44 { 45 int x=ra(),y=ra(),v=ra(); 46 dis[x][y]=dis[y][x]=min(dis[x][y],v); 47 d[x]++; d[y]++; tot+=v; 48 } 49 floyd(); 50 for (int i=1; i<=n; i++) 51 if (d[i]&1) q[++top]=i; 52 ed=bin[top]-1; 53 dp(); 54 cout<<f[ed]+tot<<endl; 55 } 56 return 0; 57 }
