1 #include<bits/stdc++.h> 2 #define ll long long 3 using namespace std; 4 const int P=1e6; 5 const int N=2e6+5; 6 const int M=2e6+5; 7 const int inf=0x3f3f3f3f; 8 struct edge 9 { 10 int f,t,next; 11 ll v; 12 }e[M]; 13 int n,m,tot,all,s,cnt,head[N],dfn[N],low[N],st[N],id[N]; 14 int dindex; 15 bool inst[N]; 16 ll num[N],sum[100005],val[N]; 17 void add(int f,int t,ll v) 18 { 19 e[tot].f=f; e[tot].t=t; e[tot].v=v; 20 e[tot].next=head[f]; head[f]=tot++; 21 } 22 void tarjan(int v) 23 { 24 dindex++; 25 dfn[v]=low[v]=dindex; 26 st[all++]=v; inst[v]=true; 27 for(int i=head[v];~i;i=e[i].next) 28 { 29 int nx=e[i].t; 30 if(!dfn[nx]) 31 { 32 tarjan(nx); 33 low[v]=min(low[v],low[nx]); 34 } 35 else if(inst[nx]) low[v]=min(low[v],dfn[nx]); 36 } 37 if(dfn[v]==low[v]) 38 { 39 cnt++; 40 while(1) 41 { 42 int cur=st[--all]; 43 inst[cur]=false; 44 id[cur]=cnt; 45 if(cur==v) break; 46 } 47 } 48 } 49 ll work(ll x) 50 { 51 ll ans=0; 52 int item=lower_bound(num,num+15001,x)-num; 53 ans-=sum[item]; 54 ans+=x*(item+1); 55 ans+=num[item]-x; 56 return ans; 57 } 58 ll dfs(int v) 59 { 60 ll res=0; 61 dfn[v]=1; 62 for(int i=head[v];~i;i=e[i].next) 63 { 64 int nx=e[i].t; 65 if(!dfn[nx]) res=max(res,e[i].v+dfs(nx)); 66 else res=max(res,val[nx]+e[i].v); 67 } 68 val[v]+=res; 69 return val[v]; 70 } 71 int main() 72 { 73 num[1]=1; cnt=0; all=0; tot=0; dindex=0; 74 for(int i=1;i<=15000;i++) num[i]=num[i-1]+i,sum[i]=sum[i-1]+num[i]; 75 memset(head,-1,sizeof(head)); 76 scanf("%d%d",&n,&m); 77 for(int i=1;i<=m;i++) 78 { 79 int f,t; ll v; 80 scanf("%d%d%lld",&f,&t,&v); 81 add(f,t,v); 82 } 83 scanf("%d",&s); 84 tarjan(s); 85 int up=tot; 86 for(int i=0;i<up;i++) 87 { 88 int a=e[i].f,b=e[i].t; 89 if(!id[a] || !id[b]) continue; 90 if(id[a]==id[b]) val[id[a]+P]+=work(e[i].v); 91 else if(id[a]<id[b]) add(id[b]+P,id[a]+P,e[i].v); 92 else add(id[a]+P,id[b]+P,e[i].v); 93 } 94 ll ans=dfs(id[s]+P); 95 printf("%lld ",ans); 96 return 0; 97 }