bzoj1208| Hnoi Travel comf| and find a collection

Description
give you an n<=500 graph, N (a) vertex, M (m<=5000) edge, each edge has a weight Vi (vi<30000). Give you two vertices s and t to find a path that minimizes the ratio of the maximum and minimum edges on the path. If there is no path between S and T, the output "impossible", otherwise the output of this ratio, if necessary, expressed as an approximate fraction. Note: There may be more than one path between two vertices.
Input
The first line contains two positive integers, N and M. The M line down contains three positive integers per line: x, Y and V. Indicates that there is a two-way road between the sights X and the attraction Y, and the vehicle must travel at speed v on the public road. The last line contains two positive integer s,t, indicating the shortest path from attraction s to the maximum minimum speed of attraction T. S and T cannot be the same.
Output
if the attraction s to attractions t have no path, output "impossible". Otherwise the output is a number that represents the minimum speed ratio. If necessary, output an approximate fraction.
Sample Input
"Sample input 1"
4 2
1 2 1
3 4 2
1 4 "Sample input 2"
3 3
1 2
1 2 5
2 3 8
1 3
"Sample input 3"
3 2
1 2 2
2 3 4
1 3
Sample Output
"Sample Output 1"
impossible "Sample Output 2"
5/4
"Sample Output 3"
2
"Data range"
1< N < =
1 < = x, y < = n,0 < v < 30000,x≠y
0 < M < =5000
Analysis: The same as the comfortable route.

#include <iostream>#include<cstdio>#include<cstring>using namespacestd;structnode{intX,y,v;} e[5001];intfa[501];BOOLCMP (node A,node b) {returna.v<B.V;}intgcdintAintb) {returnB?GCD (b,a%b): A; }intFindintx) {returnx==fa[x]?x:fa[x]=find (Fa[x]);}intMain () {intn,m; CIN>> N >>m;  for(intI=1; i<=m; i++) Cin >> e[i].x >> e[i].y >>e[i].v; Sort (e+1, e+m+1, CMP); intst=1, mx,mn; ints,t,ansmx=1, ansmn=0; CIN>> s >>T;  while(st<m) {intK;  for(intI=1; i<=n; i++) fa[i]=i;  for(inti=st; i<=m; i++) {fa[e[i].x]=find (E[I].Y); if(Find (s) ==find (t)) {mx=e[i].v; k=i; Break; } }          if(mx==-1)if(!ANSMN) {cout<<"Impossible";return 0; } Else  Break;  for(intI=1; i<=n; i++) fa[i]=i;  for(; k>=1; k--) {fa[e[k].x]=find (E[K].Y); if(Find (s) ==find (t)) {mn=e[k].v; st=k+1; Break; } }          if(mn==-1)if(!ANSMN) {cout<<"Impossible";return 0; } Else  Break; intR=GCD (MX,MN); Mx/=r; Mn/=R; if(ANSMX*MN&GT;ANSMN*MX) {ansmn=mn;ansmx=MX;} }    if(ansmn==1) cout <<Ansmx; Elsecout << ansmx <<"/"<< ANSMN <<Endl; return 0;}

bzoj1208| Hnoi Travel comf| and find a collection