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| #include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
template<typename T>inline void read(T &x)
{
int ch=getchar();
T f=1;
x=0;
while(!('0'<=ch&&ch<='9'))
{
if(ch=='-')
f=-1;
ch=getchar();
}
while('0'<=ch&&ch<='9')
{
x=(x<<3)+(x<<1)+ch-48;
ch=getchar();
}
x*=f;
}
const int N=1e4+10;
int n,m;
int head[N],to[(N*10)<<1],nxt[(N*10)<<1],w[(N*10)<<1],e;
int ans[N],cnt[N];
bool vis[N];
queue<int>q;
inline void add(const int &u,const int &v,const int &c)
{
to[++e]=v;
w[e]=c;
nxt[e]=head[u];
head[u]=e;
}
inline bool spfa(const int &s)
{
while(!q.empty())
q.pop();
memset(ans,0x3f,sizeof(ans));
memset(vis,0,sizeof(vis));
memset(cnt,0,sizeof(cnt));
ans[s]=0;
vis[s]=1;
q.push(s);
while(!q.empty())
{
int x=q.front();
q.pop();
vis[x]=0;
for(int i=head[x];i;i=nxt[i])
{
int y=to[i];
if(ans[y]>ans[x]+w[i])
{
ans[y]=ans[x]+w[i];
cnt[y]=cnt[x]+1;
if(cnt[y]>n)
return 1;
if(!vis[y])
{
vis[y]=1;
q.push(y);
}
}
}
}
return 0;
}
int main()
{
read(n);
read(m);
int u,v,w;
for(int i=1;i<=m;++i)
{
read(u);
read(v);
read(w);
add(u,v,-w);
}
if(spfa(1))
{
printf("Forever love");
return 0;
}
int res=ans[n];
if(spfa(n))
printf("Forever love");
else
printf("%d",min(res,ans[1]));
return 0;
}
|