Submission #1139018

#	Time	Username	Problem	Language	Result	Execution time	Memory
1139018		ByeWorld	Construction Project 2 (JOI24_ho_t2)	C++20	100 / 100	314 ms	33856 KiB

Main

#include <bits/stdc++.h>
#define int long long
#define ll long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
typedef pair<int,int> pii;
typedef pair<char,char> pcc;
typedef pair<int,pii> ipii;
typedef pair<pii,pii> ipiii;
const int MAXN = 3e5+50;
const int SQRT = 610;
const int MAXA = 50;
const int MOD = 998244353;
const int LOG = 21;
const int INF = 1e16+100;
const int INF2 = 1e18;
const ld EPS = 1e-12;

int n, m, s, t, l, k;
vector <pii> adj[MAXN];
priority_queue <pii, vector<pii>, greater<pii>> pq;
int dis[MAXN], dis2[MAXN];

void dji2(){
    for(int i=1; i<=n; i++) dis2[i] = INF;
    dis2[t] = 0; pq.push({0, t});
    while(!pq.empty()){
        int nw = pq.top().se, dist = pq.top().fi; pq.pop();
        if(dist > dis2[nw]) continue;
        for(auto [nx, ed] : adj[nw]){
            if(dis2[nx] > dist+ed){
                dis2[nx] = dist+ed; pq.push({dis2[nx], nx});
            }
        }
    }
}
void dji(){
    for(int i=1; i<=n; i++) dis[i] = INF;
    dis[s] = 0; pq.push({0, s});
    while(!pq.empty()){
        int nw = pq.top().se, dist = pq.top().fi; pq.pop();
        if(dist > dis[nw]) continue;
        for(auto [nx, ed] : adj[nw]){
            if(dis[nx] > dist+ed){
                dis[nx] = dist+ed; pq.push({dis[nx], nx});
            }
        }
    }
}
struct seg {
    int st[4*MAXN];
    int que(int id, int l, int r, int x, int y){
        if(x<=l && r<=y) return st[id];
        if(r<x || y<l) return 0;
        return que(lf,l,md,x,y) + que(rg,md+1,r,x,y);
    }
    int upd(int id, int l, int r, int x, int p){
        if(l==r && l==x) return st[id] += p;
        if(r<x || x<l) return st[id];
        return st[id] = upd(lf,l,md,x,p) + upd(rg,md+1,r,x,p);
    }
} A;
vector <pii> que[MAXN];
signed main(){
    // ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin>>n>>m;
    cin>>s>>t>>k>>l;
    for(int i=1; i<=m; i++){
        int x, y, z; cin>>x>>y>>z;
        adj[x].pb({y,z}); adj[y].pb({x,z});
    }
    dji(); dji2();
    // for(int i=1; i<=n; i++){
    //     cout << i << ' ' <<dis[i]<<' '<<dis2[i]<< "pp\n";
    // }

    if(dis[t] <= l){
        cout << n*(n-1)/2 << '\n'; exit(0);
    } 
    vector <int> vec;
    for(int i=1; i<=n; i++) vec.pb(dis2[i]);
    sort(vec.begin(), vec.end());
    int ans = 0;
    for(int i=1; i<=n; i++){
        int te = l-k-dis[i];
        int xx =upper_bound(vec.begin(), vec.end(), te) - vec.begin();
        // cout << i << ' ' << xx << "xx\n";
        ans += xx;
    }
    cout << ans << '\n';
}

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