| # | Time | Username | Problem | Language | Result | Execution time | Memory | 
|---|---|---|---|---|---|---|---|
| 4000 | Qwaz | Following Flow (kriii1_F) | C++98 | 0 ms | 0 KiB | 
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <cstdio>
#include <vector>
#include <queue>
const int N_MAX=35, M_MAX=1020;
struct state {
	int time, node;
	double ratio;
	bool operator < (const state &t) const {
		return time*ratio > t.time*t.ratio;
	}
};
struct edge {
	int to, time;
};
int n, m, outCount[N_MAX];
std::vector < edge > to[N_MAX];
void input(){
	scanf("%d%d", &n, &m);
	int i;
	for(i=0; i<m; i++){
		int p, q, r;
		scanf("%d%d%d", &p, &q, &r);
		edge t;
		t.time = r;
		t.to = q;
		to[p].push_back(t);
	}
}
std::priority_queue < state > pq;
double res;
void solve(){
	state now;
	now.node = 0;
	now.ratio = 1;
	now.time = 0;
	pq.push(now);
	while(true){
		now = pq.top();
		pq.pop();
		if(now.ratio < DBL_EPSILON)
			break;
		int i, size=to[now.node].size();
		for(i=0; i<size; i++){
			int next = to[now.node][i].to;
			int edgeTime = to[now.node][i].time;
			state sNext;
			sNext.node = next;
			sNext.ratio = now.ratio/size;
			sNext.time = now.time+edgeTime;
			if(next == n)
				res += sNext.ratio*sNext.time;
			else
				pq.push(sNext);
		}
	}
	printf("%.10lf\n", res);
}
int main(){
	input();
	solve();
	return 0;
}
