# 【luogu P1608 路径统计】 题解

#include <queue>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 200010;
int dis[maxn], ans[maxn], n, m, k, used[2010][2010];
bool vis[maxn];
struct edge{
int next, to, len;
}e[maxn<<2];
queue<int> q;
void add(int u, int v, int w)
{
e[++cnt].len = w;
e[cnt].to = v;
}
void SPFA()
{
while(!q.empty())
{
int now = q.front(); q.pop();
vis[now] = 0;
if(now == n) continue;
for(int i = head[now]; i != -1; i = e[i].next)
{
if(dis[e[i].to] == dis[now] + e[i].len)
{
ans[e[i].to] = (ans[e[i].to] + ans[now]);
if(!vis[e[i].to])
{
q.push(e[i].to);
vis[e[i].to] = 1;
}
}
if(dis[e[i].to] > dis[now] + e[i].len)
{
dis[e[i].to] = dis[now] + e[i].len;
ans[e[i].to] = ans[now];
if(!vis[e[i].to])
{
q.push(e[i].to);
vis[e[i].to] = 1;
}
}
}
ans[now]=0;
}
}
int main()
{
memset(dis, 127, sizeof(dis));
memset(used, 127, sizeof(used));
while(!q.empty()) q.pop();
scanf("%d%d",&n,&m);
for(int i = 1; i <= m; i++)
{
int u, v, w;
scanf("%d%d%d",&u,&v,&w);
if(used[u][v] > w)
{
used[u][v] = w;
}
}
dis[1] = 0;
vis[1] = 1;
ans[1] = 1;
q.push(1);
SPFA();
if(dis[n] >= 2139062143) {printf("No answer\n"); return 0;}
printf("%d %d\n",dis[n], ans[n]);
}

posted @ 2018-10-19 20:51  Misaka_Azusa  阅读(77)  评论(0编辑  收藏
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