Submission #1000955

#	Time	Username	Problem	Language	Result	Execution time	Memory
1000955		fryingduc	Salesman (IOI09_salesman)	C++17	100 / 100	488 ms	44176 KiB

salesman

#include "bits/stdc++.h"
using namespace std;
 
const int maxn = 5e5 + 5;
int n, d, u, s;
long long f[maxn];
const long long inf = 9e18;

int m[maxn];
 
struct info {
    int t, l, m;
    bool operator<(const info &o) {
        return (t != o.t ? t < o.t : l < o.l);
    }
} a[maxn];
 
struct segment_tree {
    int n;
    vector<long long> tree;
    segment_tree() {}
    segment_tree(int n) : n(n), tree(n * 4 + 6, -inf) {}
    void update(int ind, int l, int r, int pos, long long val) {
        if(l == r) {
            tree[ind] = max(tree[ind], val);
            return;
        }
        int mid = (l + r) / 2;
        if(pos <= mid) update(ind * 2, l, mid, pos, val);
        else update(ind * 2 + 1, mid + 1, r, pos, val);
        tree[ind] = max(tree[ind * 2], tree[ind * 2 + 1]);
    }
    long long get(int ind, int l, int r, int x, int y) {
        if(l > y || r < x) return -inf;
        if(x <= l and r <= y) return tree[ind];
        int mid = (l + r) / 2;
        return max(get(ind * 2, l, mid, x, y), get(ind * 2 + 1, mid + 1, r, x, y));
    }
    void update(int pos, long long val) {
        update(1, 1, n, pos, val);
    }
    long long get(int x, int y) {
        return get(1, 1, n, x, y);
    }
} up, down;
void solve() {
    cin >> n >> u >> d >> s;
    for(int i = 1; i <= n; ++i) {
        cin >> a[i].t >> a[i].l >> a[i].m;
    }
    up = segment_tree(maxn);
    down = segment_tree(maxn);
    
    sort(a + 1, a + n + 1);
    
    for(int i = 1; i <= n; ++i) {
        m[i] = m[i - 1] + a[i].m;
    }
    
    down.update(s, -(s * u));
    up.update(s, s * d);  
    
    long long ans = 0;
    
    for(int i = 1; i <= n; ++i) {
        int cur = 0;
        while(i + cur <= n and a[i].t == a[i + cur].t) ++cur;
        for(int j = i; j < i + cur; ++j) {
            long long cur_up = up.get(1, a[j].l - 1) - 1ll * a[j].l * d + a[j].m; 
            long long cur_down = down.get(a[j].l + 1, maxn - 1) + 1ll * a[j].l * u + a[j].m;
            
            f[j] = max(cur_up, cur_down);
        }
        long long current = f[i];
        vector<long long> suf(cur + 1, -inf), pref(cur + 1, -inf);
        vector<long long> tmp(cur, -inf);
        for(int j = i + cur - 1; j >= i; --j) {
            suf[j - i] = m[j] - a[j].l * (u + d);
            if(j < i + cur - 1) suf[j - i] = max(suf[j - i], suf[j - i + 1]);
        }
        for(int j = i; j < i + cur; ++j) {
            pref[j - i] = a[j].l * (u + d) - m[j - 1];
            if(j > i) pref[j - i] = max(pref[j - i], pref[j - i - 1]);
        }
        for(int j = i; j < i + cur; ++j) {
            if(j > i) current = max(f[j], current - (a[j].l - a[j - 1].l) * d + a[j].m);
            tmp[j - i] = current + max(0ll, suf[j - i] - m[j] + a[j].l * (u + d));
            
//            cerr << j << " " << tmp[j - i] << " " << current << '\n'; 
        }
        current = f[i + cur - 1];
        for(int j = i + cur - 1; j >= i; --j) {
            if(j < i + cur - 1) current = max(f[j], current - 1ll * (a[j + 1].l - a[j].l) * u + a[j].m);
            long long hehe = current + max(0ll, pref[j - i] + m[j - 1] - a[j].l * (u + d));
            tmp[j - i] = max(tmp[j - i], hehe);
            
//            cerr << j << " " << tmp[j - i] << " " << current << '\n';
        }
        for(int j = i; j < i + cur; ++j) {
            f[j] = max(f[j], tmp[j - i]);
            if(a[j].l >= s) {
                ans = max(ans, f[j] - 1ll * (a[j].l - s) * u);
            }
            else {
                ans = max(ans, f[j] - 1ll * (s - a[j].l) * d);
            }
            up.update(a[j].l, f[j] + 1ll * a[j].l * d);
            down.update(a[j].l, f[j] - 1ll * a[j].l * u);
            
        }
        i = i + cur - 1;
//        cerr << i << " " << f[i] << " " << cur_up << " " << cur_down << '\n';
    }
    cout << ans;
}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    solve();
    return 0;
}

• Subtask 1: 100 / 100