Submission #1217458

#	Time	Username	Problem	Language	Result	Execution time	Memory
1217458		baojiaopisu	Construction Project 2 (JOI24_ho_t2)	C++20	0 / 100	50 ms	18872 KiB

Main

#include<bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;

using pii = pair<int, int>;
using pll = pair<long long, long long>;

#define pb push_back
#define ins insert
#define fi first
#define se second
#define btpc __builtin_popcount
#define btclz __builtin_clz

#define sz(x) (int)(x.size());
#define all(x) x.begin(), x.end()
#define debug(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int d4x[4] = {1, 0, -1, 0}; int d4y[4] = {0, 1, 0, -1};
int d8x[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int d8y[8] = {1, 1, 0, -1, -1, -1, 0, 1};

template<class X, class Y>
    bool minimize(X &x, const Y &y) {
        if (x > y)
        {
            x = y;
            return true;
        }
        return false;
    }
template<class X, class Y>
    bool maximize(X &x, const Y &y) {
        if (x < y)
        {
            x = y;
            return true;
        }
        return false;
    }

const int MOD = 1e9 + 7; //998244353

/* Author : Le Ngoc Bao Anh, A5K37 Le Quy Don High School for Gifted Student, Da Nang */

/*       University of Wollongong       */

const long long INF = 1e9;
const int N = 2e5 + 10;

vector<pll> adj[N];

void BaoJiaoPisu() {
	int n, m; cin >> n >> m;
	ll S, T, L, K; cin >> S >> T >> L >> K;

	for(int i = 1; i <= m; i++) {
		int u, v, w; cin >> u >> v >> w;
		adj[u].pb({v, w});
		adj[v].pb({u, w});
	}

	auto F = [&](int S) -> vector<ll> {
		vector<ll> dist(n + 1, INF * INF);

		dist[S] = 0;
		struct PQ {
			int u; ll w;

			bool operator < (const PQ & temp) const {
				return w > temp.w;
			}
		};
		priority_queue<PQ> q;
		q.push({S, 0});
		
		while(q.size()) {
			PQ T = q.top(); q.pop();
			int u = T.u;
			if(T.w != dist[u]) continue;
			
			for(auto nxt : adj[u]) {
				int v = nxt.fi;
				ll w = nxt.se;

				if(minimize(dist[v], dist[u] + w)) q.push({v, dist[v]});
			}
		}

		return dist;
	};

	vector<ll> distS = F(S);
	vector<ll> distT = F(T);

	if(distS[T] <= K) {
		cout << 1ll * n * (n - 1) / 2;
		return;
	}

	ll ans = 0;
	sort(all(distT));

	for(int i = 0; i < n; i++) {
		int pos = -1;
		int l = 0, r = n - 1;
		while(l <= r) {
			int mid = (l + r) >> 1;
			if(distS[i] + distT[mid] + L <= K) {
				pos = mid;
				l = mid + 1;
			} else {
				r = mid - 1;
			}
		}
		ans += min(i, pos + 1);
	}

	cout << ans;
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    #ifndef ONLINE_JUDGE
    #else 
    //online
    #endif

    int tc = 1, ddd = 0;
    // cin >> tc;
    while(tc--) {
        //ddd++;
        //cout << "Case #" << ddd << ": ";
        BaoJiaoPisu();
    }
}

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