# | 제출 시각 | 아이디 | 문제 | 언어 | 결과 | 실행 시간 | 메모리 |
---|---|---|---|---|---|---|---|
1274961 | Faisal_Saqib | Construction Project 2 (JOI24_ho_t2) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long
const ll N=2e5+100;
ll dist[N],tmp=0;
vector<pair<ll,ll>> ma[N];
ll n,m;
void compute(ll s)
{
for(ll i=0;i<=n;i++)
{
dist[i]=1e18;
}
dist[s]=0;
priority_queue<pair<ll,ll>> pq;
pq.push({0,s});
while(pq.size())
{
auto it=pq.top();
pq.pop();
ll x=it.second,dt=it.first;
if(dist[x]!=dt)continue;
for(auto y:ma[it.second])
{
if(dist[y.first]>(dt+y.second))
{
dist[y.first]=dt+y.second;
pq.push({dt+y.second,y.first});
}
}
}
}
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>
void solve()
{
tmp=0;
cin>>n>>m;
ll s,t,l,k;
cin>>s>>t>>l>>k;
for(ll i=0;i<m;i++)
{
ll a,b,c;
cin>>a>>b>>c;
ma[a].pb({b,c});
ma[b].pb({a,c});
}
compute(s);
vector<ll> cur,dist1(n+2);
for(ll i=1;i<=n;i++)
{
cur.pb(dist[i]);
dist1[i]=dist[i];
}
sort(begin(cur),end(cur));
compute(t);
ll ans=0,c0=0,c1=0;;
vector<pair<ll,ll>> val;
for(ll i=1;i<=n;i++)
{
// dist(s,i) + dist(j,t) + l <= k
// OR
// dist(s,i)+dist(i,t) <=k
// OR
// dist(s,j)+dist(j,t)<=k
if(dist1[i]+dist[i] <=k )
{
ans+=c0+c1;
c1++;
}
else
{
ans+=c1;
c0++;
val.pb({dist1[i],i});
}
// We did dist(s,i)+dist(i,t) <=k or dist(s,j)+dist(j,t) <=k unordered (i,j)=(j,i)
// We need to add dist(s,i)+dist(i,t) > k and dist(s,j)+dist(j,t)>k and dist(s,i)+dist(j,t)+l<=k
// p
}
sort(begin(val),end(val));
ordered_set tp;
for(auto [kp,i]:val)
{
//try i to be with s
// dist(j,t) <= k-l-kp
ans+=tp.order_of_key(k-l-kp);
// i with t
// dist(s,j) <=k-l - dist(i,t)
ans+=upper_bound(begin(val),end(val),{k-l-dist[i],n+1})-begin(val);
tp.insert(dist[i]);
}
// ans/=2;
cout<<ans<<endl;
// sort(dist);
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
ll t=1;
// cin>>t;
while(t--)
{
solve();
}
}