NOIP2017 Day1 T3 Park (Shortest path + topology sort +DP)

God TM Game when more than 0 of the 60 T T

First run out of 1 starting point and n the shortest point, because K is only 50, so can DP. Set F[i][j] Represents the length of the shortest path I, and the number of schemes to J.

We found that if the shortest road and 0 sides will have a posterior sex, how to do? Topology ordering.

The shortest way point and 0 sides of the point out to run topology sequencing, if there are 0 ring words must not be 0, and note that 0 ring must be in the shortest path of the <= +k output-1, this is just run out of the 1 starting point to n the shortest way to the beginning to judge the good.

Then the topological sequence DP out I the same, and then DP is not on the shortest path or 0 sides.

#include <iostream>#include<cstring>#include<cstdlib>#include<cstdio>#include<queue>#defineMOD (x) ((x) >=mod? ( x)-mod: (x))using namespacestd;Const intmaxn=1000010;structtjm{inttoo, dis, pre;} e[2][MAXN];structpoi{intx, dis;}; Priority_queue<poi>Q;BOOL operator< (poi A, poi b) {returnA.dis>B.dis;}intT, x, Y, Z, N, M, K, mod, top, tot[2], ans;intf[ -][MAXN], dist[2][MAXN], last[2][MAXN], D[MAXN], ST[MAXN];voidReadint&k) {    intf=1; k=0;CharC=GetChar ();  while(c<'0'|| C>'9') c=='-'&& (f=-1), c=GetChar ();  while(c<='9'&& c>='0') k=k*Ten+c-'0', c=GetChar (); K*=F;} InlinevoidAddintXintYintZintTy) {e[ty][++tot[ty]]= (TJM) {y, Z, Last[ty][x]}; last[ty][x]=tot[ty];} InlinevoidDij (intXintty) {memset (dist[ty], +,sizeof(Dist[ty])); DIST[TY][X]=0; Q.push (POI) {x,0});  while(!Q.empty ()) {POI now=q.top (); Q.pop (); if(Dist[ty][now.x]!=now.dis)Continue;  for(intI=last[ty][now.x], too;i;i=e[ty][i].pre)if(dist[ty][too=e[ty][i].too]>dist[ty][now.x]+E[ty][i].dis) {Dist[ty][too]=dist[ty][now.x]+E[ty][i].dis;        Q.push (POI) {too, Dist[ty][too]}); }}}inlineBOOLtopo () {memset (d,0,sizeof(d));  for(intI=1; i<=n;i++)     for(intj=last[0][i], too;j;j=e[0][j].pre)if(dist[0][i]+e[0][j].dis==dist[0][too=e[0][j].too]) d[too]++; Top=0; for(intI=1; i<=n;i++)if(!d[i]) st[++top]=i;  for(intI=1; i<=top;i++)     for(intj=last[0][st[i]], too;j;j=e[0][j].pre)if(dist[0][st[i]]+e[0][j].dis==dist[0][too=e[0][j].too]) {D[too]--; if(!d[too]) st[++top]=too; }     for(intI=1; i<=n;i++)if(D[i] && dist[0][i]+dist[i][n]<=dist[0][N]+K)return 0; return 1;}intMain () {read (T);  while(t--) {memset (last,0,sizeof(last)); tot[0]=tot[1]=0; Read (n); Read (m); Read (K);        Read (mod);  for(intI=1; i<=m;i++) Read (x), read (y), read (z), add (x, Y, Z,0), add (y, X, Z,1); Dij (1,0); DIJ (N,1); if(!topo ()) {Puts ("-1");Continue;} Memset (F,0,sizeof(f)); f[0][1]=1; ans=0;  for(intI=0; i<=k;i++)        {             for(intj=1; j<=top;j++)              for(intk=last[0][ST[J]], too;k;k=e[0][k].pre)if(e[0][k].dis+dist[0][st[j]]==dist[0][too=e[0][k].too]) F[i][too]+=F[I][ST[J]], f[i][too]=MOD (F[i][too]);  for(intj=1; j<=n;j++)             for(intk=last[0][J], too, tmp;k;k=e[0][k].pre)if((tmp=i+e[0][k].dis+dist[0][j]-dist[0][too=e[0][k].too]) <=k && i!=tmp) F[tmp][too]+=F[I][J], f[tmp][too]=MOD (F[tmp][too]); Ans+=f[i][n]; ans=MOD (ans); } printf ("%d\n", ans); }}

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NOIP2017 Day1 T3 Park (Shortest path + topology sort +DP)