delete pics to save space

1.3953.cpp

@@ -0,0 +1,88 @@
+#include<cstdio>
+#include<cstring>
+#include<queue>
+#include<algorithm>
+using namespace std;
+template<typename T> inline void read(T& t)
+{
+    t=0; int ch,f=false;
+    while(ch=getchar(),!((ch>='0'&&ch<='9')||ch=='-'));
+    if(ch=='-') f=true,ch=getchar();
+    t=ch^48;
+    while(ch=getchar(),ch>='0'&&ch<='9') t=t*10+(ch^48);
+    if(f) t=-t;
+}
+template<typename T,typename... Args> inline void read(T& t,Args&... args) { read(t); read(args...); }
+const int maxn=100005;
+const int maxm=200005;
+int T;
+int N,M,K,P;
+struct Edge { int v,w; Edge *next; };
+struct Graph
+{
+	Edge mem[maxm*2],*G[maxn],*ecnt;
+	inline void init() { memset(G,0,sizeof(G)); ecnt=mem; } 
+	inline void AddEdge(int u,int v,int w) { ecnt->v=v; ecnt->w=w; ecnt->next=G[u]; G[u]=ecnt++; }
+};
+Graph G,inv;
+struct Node { int u,dis; };
+inline bool operator<(const Node &a,const Node &b) { return a.dis>b.dis; } 
+int d[maxn],vis[maxn];
+void dijstra()
+{
+	memset(vis,0,sizeof(vis)); memset(d,0x3f,sizeof(d));
+	d[N]=0;
+	priority_queue<Node> Q;
+	Q.push((Node){N,0});
+	while(Q.size())
+	{
+		int u=Q.top().u,dis=Q.top().dis; Q.pop();
+		if(vis[u]) continue;
+		vis[u]=true;
+		for(Edge *it=inv.G[u];it;it=it->next)
+			if(d[it->v]>dis+it->w)
+			{
+				d[it->v]=dis+it->w;
+				Q.push((Node){it->v,d[it->v]});
+			}
+	}
+}
+int in[maxn][55],f[maxn][55];
+int dfs(int u,int k)
+{
+	if(in[u][k]) return -1;
+	if(f[u][k]) return f[u][k];
+	in[u][k]=true; if(u==N) f[u][k]=1;
+	for(Edge *it=G.G[u];it;it=it->next)
+	{
+		int tp,v,w;
+		if((tp=d[v=it->v]-d[u]+it->w)<=k)
+		{
+			if((w=dfs(v,k-tp))==-1) return f[u][k]=-1;
+			f[u][k]=(f[u][k]+w)%P;
+		}
+	}
+	in[u][k]=0;
+	return f[u][k];
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&T);
+	while(T-->0)
+	{
+		read(N,M,K,P);
+		G.init(); inv.init();
+		while(M-->0)
+		{
+			int u,v,w; read(u,v,w);
+			G.AddEdge(u,v,w); inv.AddEdge(v,u,w);
+		}
+		dijstra();
+		memset(in,0,sizeof(in)); memset(f,0,sizeof(f));
+		printf("%d\n",dfs(1,K));
+	}
+	return 0;
+}