poj 2472 106 miles to Chicago

//poj 2472 106 miles to Chicago
/*
*  因为求安全性最大的路径，所以可以将dist[1]定为-1,再作spfa处理
* spfa(st) 之后有dist[]得到距离
*/
//licatweijei
#include<iostream>

using namespace std;

#define INF 1000000
#define MAXE 10100
#define MAXV 10100
#include <queue>
#include <cstring>
#include <iomanip>

double dist[MAXV];
deque<int> pqu;
bool visited[MAXV];
int cnt[MAXV];
int last[MAXV];

struct edge
{
int x,y;
double d;
int next;
}edges[MAXE];
int len;
int first[MAXV];
int V; // to be difine

void init(int v)
{
memset(cnt,0,sizeof(cnt));
memset(visited,false,sizeof(visited));
memset(first,0,sizeof(first));
memset(last,0,sizeof(last));
len = 0;
V = v;

}

void add_edge(int x,int y,double d)
{
++len;
edges[len].x = x;
edges[len].y = y;
edges[len].d = d;
edges[len].next = first[x];
first[x] = len;
}

bool spfa(int st)
{
for (int i=0;i<=V;i++)
{
dist[i] = INF;
}
dist[st] = -1;
visited[st] = true;
pqu.push_front(st);
while(!pqu.empty()){
int now = pqu.front();
pqu.pop_front();
visited[now] = false;
for (int nt = first[now];nt!=0;nt = edges[nt].next){
if (edges[nt].d * dist[now] < dist[edges[nt].y] ) {
dist[edges[nt].y] =  edges[nt].d * dist[now];
last[edges[nt].y] = now;
if (!visited[edges[nt].y]){
visited[edges[nt].y] = true;
cnt[edges[nt].y]++;
if (cnt[edges[nt].y]>V) return false;
if (!pqu.empty()){
if (dist[edges[nt].y]>dist[pqu.front()])
pqu.push_back(edges[nt].y);
else
pqu.push_front(edges[nt].y);
} else pqu.push_front(edges[nt].y);
}
}
}
}
return true;
}

int main (void)
{
int n,m;
while(cin >> n ){
if (n==0) break;
cin >> m;
init(n);
int x,y;
double d;
for (int i=0;i<m;i++){
cin >> x >> y >> d;
d/=100;
add_edge(x,y,d);
add_edge(y,x,d);
}
spfa(1);
cout << setiosflags(ios::fixed) << setprecision(6) << -dist
*100 << " percent" << endl;
}
}