BZOJ1975: [Sdoi2010]魔法猪学院

来源：互联网发布：约瑟夫环c 数组编辑：程序博客网时间：2024/05/08 09:13
第一道A*。。。
今天才会做k短路。。。。
#include<cstdio>#include<iostream>#include<cstring>#include<cstdlib>#include<queue>using namespace std;struct Node{int x;double dis;inline friend bool operator<(Node a,Node b){return a.dis>b.dis;}};struct node{double f,g;int v;inline friend bool operator<(node a,node b){return a.f>b.f;}};priority_queue<Node> Q;struct Chain{int other;double len;Chain*next;Chain(){next=NULL;}}*Head[10001],*OP_Head[10001];double Dis_To[5001];const int INF=1<<29;int n;inline void dij(int start){while(!Q.empty())Q.pop();Q.push((Node){start,0});Node tp;int i;for(i=1;i<=n;i++)  Dis_To[i]=INF;while(true){    while(Dis_To[Q.top().x]!=INF&&!Q.empty())       Q.pop();if(Q.empty())        return ;    tp=Q.top();    Dis_To[tp.x]=tp.dis;    for(Chain *tpp=OP_Head[tp.x];tpp;tpp=tpp->next)      Q.push((Node){tpp->other,tpp->len+tp.dis });}}priority_queue<node> QQ;int cnt[5001];double eps=1e-7;inline void STAR(int start,int end,double Max){while(!QQ.empty())QQ.pop();QQ.push((node){Dis_To[start],0,start});    node tp;while(!QQ.empty())       {      tp=QQ.top();QQ.pop();    if(tp.f-eps>Max)continue;    cnt[tp.v]++;    if(tp.v==end){Max-=tp.g;continue;}for(Chain*T=Head[tp.v];T;T=T->next)  if(Dis_To[T->other]!=INF)   QQ.push((node){tp.g+T->len+Dis_To[T->other],tp.g+T->len,T->other});   }printf("%d\n",cnt[end]);}char c;inline void read(int &a){a=0;do c=getchar();while(c<'0'||c>'9');while(c<='9'&&c>='0')a=(a<<3)+(a<<1)+c-'0',c=getchar();}inline void add_Head(int a,int b,double dis){Chain*tp=new Chain;tp->other=b;tp->len=dis;tp->next=Head[a];Head[a]=tp;}inline void add_OP_Head(int a,int b,double dis){Chain*tp=new Chain;tp->other=b;tp->len=dis;tp->next=OP_Head[a];OP_Head[a]=tp;}int main(){int m;read(n),read(m);double Max;    scanf("%lf",&Max);    double t;    int i,j,k;    for(i=1;i<=m;i++)      read(j),read(k),scanf("%lf",&t),add_Head(j,k,t),add_OP_Head(k,j,t);dij(n);STAR(1,n,Max);return 0;}
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