Accepted/1444K/297MS
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#include <functional> | |
#include <algorithm> | |
#include <iostream> | |
#include <fstream> | |
#include <sstream> | |
#include <utility> | |
#include <vector> | |
#include <queue> | |
#include <stack> | |
#include <list> | |
#include <map> | |
#include <set> | |
#include <cstring> | |
#include <cstdio> | |
#include <cmath> | |
#define x first | |
#define y second | |
using namespace std; | |
const int maxn=10005; | |
typedef pair<int,int> pii; | |
vector <pii> e[maxn]; | |
vector <int> dep; | |
typedef vector <pii>::iterator piii; | |
typedef vector <int>::iterator ii; | |
int n,size,s[maxn],f[maxn],root,d[maxn],k,ans; | |
bool vis[maxn]; | |
void getroot(int now,int fa) | |
{ | |
int u; | |
s[now]=1;f[now]=0; | |
for (piii v=e[now].begin();v!=e[now].end();v++) | |
{ | |
if ((u=v->x)!=fa && !vis[u]) | |
{ | |
getroot(u,now); | |
s[now]+=s[u]; | |
f[now]=max(f[now],s[u]); | |
} | |
} | |
f[now]=max(f[now],size-s[now]); | |
if (f[now]<f[root]) | |
root=now; | |
} | |
void getdep(int now,int fa) | |
{ | |
int u; | |
dep.push_back(d[now]); | |
s[now]=1; | |
for (piii v=e[now].begin();v!=e[now].end();v++) | |
{ | |
if ((u=v->x)!=fa && !vis[u]) | |
{ | |
d[u]=d[now]+v->y; | |
getdep(u,now); | |
s[now]+=s[u]; | |
} | |
} | |
} | |
int calc(int now,int init) | |
{ | |
dep.clear();d[now]=init; | |
getdep(now,0); | |
sort(dep.begin(),dep.end()); | |
int ret=0; | |
for (ii l=dep.begin(),r=dep.end()-1;l<r;) | |
{ | |
if (*l+*r<=k) | |
ret+=r-l++; | |
else | |
r--; | |
} | |
return ret; | |
} | |
void work(int now) | |
{ | |
int u; | |
ans+=calc(now,0); | |
vis[now]=1; | |
for (piii v=e[now].begin();v!=e[now].end();v++) | |
{ | |
if (!vis[u=v->x]) | |
{ | |
ans-=calc(u,v->y); | |
f[0]=size=s[u]; | |
getroot(u,root=0); | |
work(root); | |
} | |
} | |
} | |
int main() | |
{ | |
while ((~scanf("%d%d",&n,&k)) && n) | |
{ | |
for (int i=0;i<=n;i++) | |
e[i].clear(); | |
memset(vis,0,sizeof(vis)); | |
int u,v,l; | |
for (int i=1;i<n;i++) | |
{ | |
scanf("%d%d%d",&u,&v,&l); | |
e[u].push_back(pii(v,l)); | |
e[v].push_back(pii(u,l)); | |
} | |
f[0]=size=n; | |
getroot(1,root=0); | |
ans=0; | |
work(root); | |
printf("%d\n",ans); | |
} | |
return 0; | |
} |
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