Submission #761065

#	Time	Username	Problem	Language	Result	Execution time	Memory
761065		GrindMachine	Salesman (IOI09_salesman)	C++17	65 / 100	361 ms	59088 KiB

salesman

// Om Namah Shivaya

#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) 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

/*



*/

const int MOD = 1e9 + 7;
int N = 5e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

template<typename T>
struct segtree {
    // https://codeforces.com/blog/entry/18051

    /*=======================================================*/

    struct data {
        ll a;
    };

    data neutral = {-inf2};

    data merge(data &left, data &right) {
        data curr;
        curr.a = max(left.a,right.a);
        return curr;
    }

    void create(int i, T v) {
        tr[i].a = v;
    }

    void modify(int i, T v) {
        amax(tr[i].a, v);
    }

    /*=======================================================*/

    int n;
    vector<data> tr;

    segtree() {

    }

    segtree(int siz) {
        init(siz);
    }

    void init(int siz) {
        n = siz;
        tr.assign(2 * n, neutral);
    }

    void build(vector<T> &a, int siz) {
        rep(i, siz) create(i + n, a[i]);
        rev(i, n - 1, 1) tr[i] = merge(tr[i << 1], tr[i << 1 | 1]);
    }

    void pupd(int i, T v) {
        modify(i + n, v);
        for (i = (i + n) >> 1; i; i >>= 1) tr[i] = merge(tr[i << 1], tr[i << 1 | 1]);
    }

    data query(int l, int r) {
        data resl = neutral, resr = neutral;

        for (l += n, r += n; l <= r; l >>= 1, r >>= 1) {
            if (l & 1) resl = merge(resl, tr[l++]);
            if (!(r & 1)) resr = merge(tr[r--], resr);
        }

        return merge(resl, resr);
    }
};

void solve(int test_case)
{
    ll n,U,D,s; cin >> n >> U >> D >> s;
    vector<array<ll,3>> a(n+5);
    rep1(i,n) rep(j,3) cin >> a[i][j];

    sort(a.begin()+1, a.begin()+n+1);

    a[0] = {0,s,0};
    a[n+1] = {inf1,s,0};

    vector<ll> here[N];
    rep1(i,n) here[a[i][0]].pb(i);

    bool distinct = true;

    rep(i,N){
        if(sz(here[i]) >= 2){
            distinct = false;
        }
    }

    if(distinct){
        vector<ll> dp(n+5,-inf2);
        segtree<ll> st1(N), st2(N);
        
        dp[0] = 0;
        st1.pupd(s,s*D), st2.pupd(s,-s*U);
     
        rep1(i,n+1){
            auto [t,x,add] = a[i];
     
            ll v1 = st1.query(1,x).a - x*D + add;
            ll v2 = st2.query(x,N-1).a + x*U + add;
            dp[i] = max(v1,v2);
     
            st1.pupd(x,dp[i]+x*D);
            st2.pupd(x,dp[i]-x*U);
        }
     
        ll ans = dp[n+1];
        cout << ans << endl;

        return;
    }

    N = 5e3 + 5;

    vector<ll> dp(N,-inf2);
    dp[s] = 0;

    rep(t,N){
        if(here[t].empty()) conts;

        vector<ll> p(N);
        trav(i,here[t]){
            auto [t_,x,add] = a[i];
            p[x] += add;
        }

        rep1(i,N-1) p[i] += p[i-1];

        vector<ll> pref_dp(N,-inf2), pref_mx(N,-inf2);
        vector<ll> suff_dp(N,-inf2), suff_mx(N,-inf2);

        rep1(i,N-2){
            pref_dp[i] = max(pref_dp[i-1], dp[i] - p[i-1] + i*D);
            pref_mx[i] = max(pref_mx[i-1], -p[i-1] + i*U + i*D);
        }

        rev(i,N-2,1){
            suff_dp[i] = max(suff_dp[i+1], dp[i] + p[i] - i*U);
            suff_mx[i] = max(suff_mx[i+1], p[i] - i*D - i*U);
        }

        rep1(i,N-2){
            ll v1 = pref_dp[i] + suff_mx[i] + i*U;
            ll v2 = pref_mx[i] + suff_dp[i] - i*D;
            dp[i] = max({v1,v2,dp[i]});
        }
    }

    ll ans = dp[s];
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 65 / 100