Submission #1046369

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046369		YassineBenYounes	Construction Project 2 (JOI24_ho_t2)	C++17	0 / 100	2 ms	6748 KiB

Main

#include<bits/stdc++.h>
#include<chrono>
#include<random>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double db;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);} // least common multiple (PPCM)
int dx[8] = {1, 0, 0, -1, 1, 1, -1, -1};
int dy[8] = {0, 1, -1, 0, 1, -1, -1, 1};
#define endl "\n"
#define ss second
#define ff first
#define all(x) (x).begin() , (x).end()
#define pb push_back
#define vi vector<int>
#define vii vector<pair<int,int>>
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd  pair<double,double>
#define vdd  vector<pdd>
#define speed ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pbds tree<pii, null_type, less<pii>,rb_tree_tag, tree_order_statistics_node_update>
using namespace __gnu_pbds;
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

////////////////////Only Clear Code//////////////////////////

void usaco_problem(){
    freopen("milkvisits.in", "r", stdin);
    freopen("milkvisits.out", "w", stdout);
}

void init(){
    #ifndef ONLINE_JUDGE

freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif // ONLINE_JUDGE
}
const int mx = 2e5+5;
const int LOG = 22;
const int inf = 1e9;
const ll mod = 1e9+7;
const int sq = 300;

int n, m;
ll s, t, l, k;
ll distances_s[mx], distances_t[mx];

vii graph[mx];
bool vis[mx];
int32_t main(){
    init();
    speed;
    cin >> n >> m;
    cin >> s >> t >> l >> k;
    while(m--){
        int a, b, c;cin >> a >> b >> c;
        graph[a].pb({b, c});
        graph[b].pb({a, c});
    }
    for(int i = 1; i <= n;i++){
        distances_s[i] = distances_t[i] = 1e18;
    }
    priority_queue<pll, vll, greater<pll>> pq;
    distances_s[s] = 0;
    pq.push({0, s});
    while(!pq.empty()){
        int node = pq.top().ss;
        ll dis = pq.top().ff;
        pq.pop();
        if(vis[node])continue;
        vis[node] = 1;
        for(pii adj : graph[node]){
            ll nw = dis + adj.ss;
            if(nw < distances_s[adj.ff]){
                distances_s[adj.ff] = nw;
                pq.push({nw, adj.ff});
            }
        }
    }
    memset(vis, 0, sizeof vis);
    distances_t[t] = 0;
    pq.push({0, t});
    while(!pq.empty()){
        int node = pq.top().ss;
        ll dis = pq.top().ff;
        pq.pop();
        if(vis[node])continue;
        vis[node] = 1;
        for(pii adj : graph[node]){
            ll nw = dis + adj.ss;
            if(nw < distances_t[adj.ff]){
                distances_t[adj.ff] = nw;
                pq.push({nw, adj.ff});
            }
        }
    }
    /*for(int i = 1; i <= n;i++){
        cout << i << " " << distances_s[i] << " " << distances_t[i] << endl;
    }*/
    for(int i = 1; i <= n;i++){
        ll tot = distances_s[i] + distances_t[i];
        if(tot <= k){
            cout << (n*(n-1))/2 << endl;
            return 0;
        }
    }
    ll ans = 0;
    k-=l;
    for(int i = 1; i <= n;i++){
        for(int j = 1;j <= n;j++){
            ll tot = distances_s[i] + distances_t[j];
            if(tot <= k){
                ans++;
            }
        }
    }
    cout << ans << endl;
}

/*
    NEVER GIVE UP!
    DOING SMTHNG IS BETTER THAN DOING NTHNG!!!
    Your Guide when stuck:
    - Continue keyword only after reading the whole input
    - Don't use memset with testcases
    - Check for corner cases(n=1, n=0)
    - Check where you declare n(Be careful of declaring it globally and in main)
*/

Compilation message (stderr)

Main.cpp: In function 'void usaco_problem()':
Main.cpp:36:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |     freopen("milkvisits.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:37:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |     freopen("milkvisits.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp: In function 'void init()':
Main.cpp:43:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 | freopen("input.txt", "r", stdin);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:44:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 | freopen("output.txt", "w", stdout);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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