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OI-source/history_source/ccf 基础篇/U6/6.5.1.cpp
2023-08-03 09:22:52 +08:00

169 lines
2.5 KiB
C++

#include<iostream>
using namespace std;
struct con
{
int a,b;
};
con *cont;int len;
template<class T_fsort>
void fsort(T_fsort *left,T_fsort *right,bool (*cmp)(T_fsort a,T_fsort b),T_fsort *k)
{
if(right-left<=1) return;
unsigned int len=right-left;
fsort(left,left+len/2,cmp,k);
fsort(left+len/2,right,cmp,k+len/2);
int i=0,j=len/2,n=0;
while(i<len/2&&j<len)
{
if(cmp(left[i],left[j])) k[n++]=left[i++];
else k[n++]=left[j++];
}
while(i<len/2) k[n++]=left[i++];
while(j<len) k[n++]=left[j++];
for(int i=0;i<len;i++) left[i]=k[i];
}
template<class Tb_fsort>
void fsort(Tb_fsort *left,Tb_fsort *right,bool (*cmp)(Tb_fsort a,Tb_fsort b))
{
if(right-left<=1) return;
unsigned int len=right-left;
Tb_fsort k[len];
fsort(left,right,cmp,k);
}
bool cmp(con a,con b)
{
if(a.a<b.a) return 1;
if(a.a>b.a) return 0;
return a.b<b.b;
}
con* road(int a)
{
con *left,*right,*mid;
left=cont;
right=cont+len;
while(left<right)
{
mid=left+(right-left)/2;
if(mid->a>a) right=mid;
if(mid->a<a) left=mid;
if(mid->a==a)
{
left=mid;
break;
}
}
if(left->a!=a) return 0;
while(left>=cont&&left->a==a) left--;
left++;
return left;
}
template<class T_queue>
struct Node_queue
{
T_queue num;
Node_queue *next;
};
template<class a_queue>
struct queue
{
Node_queue<a_queue> *head,*tail;
int SIZE_queue;
void beginning()
{
head=tail=new Node_queue<a_queue>;
tail->next=head;
SIZE_queue=0;
}
bool push(a_queue s)
{
SIZE_queue++;
tail->num=s;
if(tail->next==head)
{
tail->next=new Node_queue<a_queue>;
tail->next->next=head;
tail=tail->next;
return 1;
}
tail=tail->next;
return 0;
}
bool pop()
{
if(head==tail) return 1;
head=head->next;
SIZE_queue--;
return 0;
}
a_queue front()
{
return head->num;
}
int size()
{
return SIZE_queue;
}
};
struct BFS
{
int num;
int step;
};
int main()
{
int n,m,p;
ios::sync_with_stdio(0);
cin>>n>>m>>p;
cont=new con[m*2+10];
con* x;
int u,v;
for(int i=0;i<m;i++)
{
cin>>u>>v;
cont[len].a=u;
cont[len].b=v;
len++;
cont[len].b=u;
cont[len].a=v;
len++;
}
fsort(cont,cont+len,cmp);
bool guo[n+1]={0,1};
queue<BFS>bfs;
bfs.beginning();
BFS r;
r.num=1;
r.step=0;
bfs.push(r);
while(bfs.size()>0&&bfs.front().step<=p)
{
x=road(bfs.front().num);
if(x!=0)
{
while(x->a==bfs.front().num)
{
if(!guo[x->b])
{
r.num=x->b;
r.step=bfs.front().step+1;
bfs.push(r);
guo[x->b]=1;
}
x++;
}
}
bfs.pop();
}
int ans=0;
for(int i=0;i<n+1;i++) ans+=guo[i];
cout<<ans<<endl;
return 0;
}
/*
4 4 2
1 2
1 3
2 3
3 4
*/