// Graphs as a Service // Solution by Jacob Plachta #define DEBUG 0 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define LL long long #define LD long double #define PR pair #define Fox(i,n) for (i=0; i=0; i--) #define FoxR1(i,n) for (i=n; i>0; i--) #define FoxRI(i,a,b) for (i=b; i>=a; i--) #define Foxen(i,s) for (i=s.begin(); i!=s.end(); i++) #define Min(a,b) a=min(a,b) #define Max(a,b) a=max(a,b) #define Sz(s) int((s).size()) #define All(s) (s).begin(),(s).end() #define Fill(s,v) memset(s,v,sizeof(s)) #define pb push_back #define mp make_pair #define x first #define y second template T Abs(T x) { return(x<0 ? -x : x); } template T Sqr(T x) { return(x*x); } string plural(string s) { return(Sz(s) && s[Sz(s)-1]=='x' ? s+"en" : s+"s"); } const int INF = (int)1e9; const LD EPS = 1e-12; const LD PI = acos(-1.0); #if DEBUG #define GETCHAR getchar #else #define GETCHAR getchar_unlocked #endif bool Read(int &x) { char c,r=0,n=0; x=0; for(;;) { c=GETCHAR(); if ((c<0) && (!r)) return(0); if ((c=='-') && (!r)) n=1; else if ((c>='0') && (c<='9')) x=x*10+c-'0',r=1; else if (r) break; } if (n) x=-x; return(1); } int main() { if (DEBUG) freopen("in.txt","r",stdin); // vars int T,t; int N,M; int i,j,k; int X[1000],Y[1000],Z[1000]; int dist[50][50]; // testcase loop Read(T); Fox1(t,T) { // init Fill(dist,60); // input Read(N),Read(M); Fox(i,M) { Read(X[i]),Read(Y[i]),Read(Z[i]),X[i]--,Y[i]--; dist[X[i]][Y[i]]=dist[Y[i]][X[i]]=Z[i]; } // Floyd's Fox(i,N) Fox(j,N) Fox(k,N) Min(dist[j][k],dist[j][i]+dist[i][k]); // check validity, and output printf("Case #%d: ",t); Fox(i,M) if (dist[X[i]][Y[i]]!=Z[i]) { printf("Impossible\n"); goto Done; } printf("%d\n",M); Fox(i,M) printf("%d %d %d\n",X[i]+1,Y[i]+1,Z[i]); Done:; } return(0); }