Submission #1071266

#	Time	Username	Problem	Language	Result	Execution time	Memory
1071266		GrindMachine	Closing Time (IOI23_closing)	C++17	75 / 100	1030 ms	46144 KiB

closing

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
 
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
 
template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}
 
template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}
 
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
 
/*
 
refs:
https://codeforces.com/blog/entry/121499
 
*/
 
const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
 
#include "closing.h"
 
vector<pll> adj[N];
ll dis[N][2];
 
void dfs1(ll u, ll p, ll t){
    for(auto [v,w] : adj[u]){
        if(v == p) conts;
        dis[v][t] = dis[u][t]+w;
        dfs1(v,u,t);
    }
}
 
vector<bool> on_path(N);
vector<ll> path;
vector<ll> curr_path;
 
void dfs2(ll u, ll p, ll des){
    curr_path.pb(u);
 
    if(u == des){
        path = curr_path;
        trav(v,curr_path){
            on_path[v] = 1;
        }
    }
 
    for(auto [v,w] : adj[u]){
        if(v == p) conts;
        dfs2(v,u,des);
    }
 
    curr_path.pop_back();
}
 
int max_score(int n, int X, int Y, long long K,
              std::vector<int> U, std::vector<int> V, std::vector<int> W)
{
    rep(i,n){
        adj[i].clear();
        on_path[i] = 0;
    }
 
    rep(i,n-1){
        ll u = U[i], v = V[i], w = W[i];
        adj[u].pb({v,w}), adj[v].pb({u,w});
    }
 
    dis[X][0] = dis[Y][1] = 0;    
    dfs1(X,-1,0);
    dfs1(Y,-1,1);
    dfs2(X,-1,Y);
 
    vector<ll> a(n), b(n);
    rep(i,n){
        ll dx = dis[i][0], dy = dis[i][1];
        a[i] = min(dx,dy);
        b[i] = max(dx,dy)-a[i];
    }
 
    ll ans = 0;
 
    // only 1s
    {
        vector<ll> vals;
        rep(i,n) vals.pb(a[i]);
        sort(all(vals));
        ll sum = 0;
        ll guys = 0;
 
        rep(i,n){
            sum += vals[i];
            if(sum > K) break;
            guys++;
        }
 
        amax(ans,guys);
    }
 
    // 1s and 2s
    // all guys on path from X to Y must be at least 1
    vector<ll> dp1(2*n+5,inf2), dp2(2*n+5);
    dp1[0] = 0;
 
    rep(i,n){
        if(on_path[i]) conts;

        fill(all(dp2),inf2);
        rep(j,2*n+1){
            // 0
            amin(dp2[j],dp1[j]);
 
            // 1
            amin(dp2[j+1],dp1[j]+a[i]);
 
            // 2
            amin(dp2[j+2],dp1[j]+a[i]+b[i]);
        }
 
        dp1 = dp2;
    }
            
    ll path_cost1 = 0;
    rep(i,sz(path)){
        ll u = path[i];
        path_cost1 += min(dis[u][0],dis[u][1]);
    }

    vector<ll> smn(2*n+5,inf2);
    rev(j,2*n,0) smn[j] = min(smn[j+1],dp1[j]);

    rep(i,sz(path)){
        ll cost = path_cost1;
        ll val = sz(path);
        for(int j = i; j < sz(path); ++j){
            ll u = path[j];
            cost += max(dis[u][0],dis[u][1])-min(dis[u][0],dis[u][1]);
            val++;
            if(cost > K) break;
            ll mx_allowed = K-cost;
            ll lo = 0, hi = 2*n;
            ll best = -1;
            while(lo <= hi){
                ll mid = (lo+hi) >> 1;
                if(mx_allowed >= smn[mid]){
                    best = mid;
                    lo = mid+1;
                }
                else{
                    hi = mid-1;
                }
            }

            assert(best != -1);
            amax(ans,val+best);
        }
    }

    return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 8
• Subtask 2: 9 / 9
• Subtask 3: 12 / 12
• Subtask 4: 14 / 14
• Subtask 5: 9 / 9
• Subtask 6: 11 / 11
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 0 / 17