Submission #1262152

#	Time	Username	Problem	Language	Result	Execution time	Memory
1262152		notisora	Construction Project 2 (JOI24_ho_t2)	C++20	45 / 100	41 ms	18600 KiB

Main

///NotIsora
///This is my last dance
#include<bits/stdc++.h>
#define modulo 1000000007
#define fi first
#define se second
#define sq(x) (x)*(x)
#define ll long long
#define ld long double
#define el '\n'
#define pb push_back
///#define int long long

using namespace std;

const int N=2e5+5;
const ll INF=1e18;

int n,m;
int st,ed,l;
ll k;
ll d[2][N];
vector<pair<int,int>>adj[N];

struct State{
    int s,type;
    ll dis;
    bool operator < (const State&other) const{
        return dis>other.dis;
    }
};

bool check(){
    if (l>1 || k>2) return 0;
    for(int i=1;i<=n;i++){
        for(pair<int,int>&pr:adj[i]){
            if (pr.se>1){
                return 0;
            }
        }
    }
    return 1;
}

signed main(){
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //freopen("i.INP","r",stdin);
    cin>>n>>m;
    cin>>st>>ed>>l>>k;
    for(int i=1;i<=m;i++){
        int a,b,w;
        cin>>a>>b>>w;
        adj[a].pb({b,w});
        adj[b].pb({a,w});
    }

    for(int i=1;i<=n;i++){
        d[0][i]=d[1][i]=INF;
    }

    priority_queue<State>pq;

    d[0][st]=0;
    d[1][ed]=0;
    pq.push({st,0,0LL});
    pq.push({ed,1,0LL});

    while(!pq.empty()){
        int s=pq.top().s;
        int t=pq.top().type;
        ll dis=pq.top().dis;
        pq.pop();

        if (dis>d[t][s]) continue;

        for(pair<int,int>&pr:adj[s]){
            int u=pr.fi;
            int w=pr.se;
            if (d[t][u]>d[t][s]+(ll)w){
                d[t][u]=d[t][s]+(ll)w;
                pq.push({u,t,d[t][u]});
            }
        }
    }

    ll ans=0;
    if (check()){
        int stcnt=0,edcnt=0;
        if (d[0][n]<=k){
            cout<<1LL*n*(n-1)/2;
            return 0;
        }
        for(int i=1;i<=n;i++){
            if (d[0][i]==1) ans++;
            if (d[1][i]==1) ans++;
        }
        ans++;
        cout<<ans;
        return 0;
    }
    for(int u=1;u<=n;u++){
        for(int v=u+1;v<=n;v++){
            if (d[0][ed]<=k) ans++;
            else{
                if (d[0][u]+(ll)l+d[1][v]<=k) ans++;
                if (d[1][u]+(ll)l+d[0][v]<=k) ans++;
            }
        }
    }
    cout<<ans;
}

• Subtask 1: 0 / 8
• Subtask 2: 16 / 16
• Subtask 3: 29 / 29
• Subtask 4: 0 / 47