Submission #1100568

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100568		vjudge1	Construction Project 2 (JOI24_ho_t2)	C++17	100 / 100	198 ms	31416 KiB

Main

#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define pb push_back
#define ii pair<int, int>
#define sz(v) (int)v.size()
#define all(v) v.begin(), v.end()
using namespace std;

const int N=2e5+5, mod = 1e9+7, inf = 1e18;

int n, m, s, t, l, k;
int ds[N], dt[N];
vector<ii> adj[N];
priority_queue<ii,vector<ii>,greater<ii>> pq;

signed main() {
    //freopen("tmp.inp", "r", stdin);
    //freopen("tmp.out", "w", stdout);
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> m >> s >> t >> l >> k;
    
    for(int i=1; i<=m; i++) {
        int a, b, c; cin >> a >> b >> c;
        adj[a].push_back({b, c});
        adj[b].push_back({a, c});
    }
    
    for (int i=1; i<=n; i++) ds[i] = inf;
    ds[s] = 0; pq.push({0, s});
    while(!pq.empty()) {
        int u = pq.top().se, d = pq.top().fi; pq.pop();
        if(d>ds[u]) continue;
        for (auto [v, w]: adj[u]) {
            if(ds[v]>ds[u]+w) {
                ds[v] = ds[u]+w;
                pq.push({ds[v], v});
            }
        }
    }

    for (int i=1; i<=n; i++) dt[i] = inf;
    dt[t] = 0; pq.push({0, t});
    while(!pq.empty()) {
        int u = pq.top().se, d = pq.top().fi; pq.pop();
        if(d>dt[u]) continue;
        for (auto [v, w]: adj[u]) {
            if(dt[v]>dt[u]+w) {
                dt[v] = dt[u]+w;
                pq.push({dt[v], v});
            }
        }
    }
    for(int i=1; i<=n; i++) {
        if(ds[i]+dt[i]<=k) {
            cout << n*(n-1)/2;
            return 0;   
        }
    }
    int ans = 0;
    sort(ds+1, ds+n+1); sort(dt+1, dt+n+1);
    for(int i=1; i<=n; i++) {
        int pos = upper_bound(dt+1, dt+n+1, k-l-ds[i])-dt-1;
        ans += pos;
    }
    cout << ans;
}

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