Submission #122048

#	Time	Username	Problem	Language	Result	Execution time	Memory
122048		egorlifar	Bulldozer (JOI17_bulldozer)	C++17	55 / 100	2035 ms	17380 KiB

bulldozer

/*
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 */
#include <iostream>
#include <complex>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
#include <random>
#include <chrono>
 
using namespace std;

template<class T1, class T2> inline int chkmin(T1 &x, const T2 &y) {
    if (x > y) {
        x = y;
        return 1;
    }
    else {
        return 0;
    }
}

template<class T1, class T2> inline int chkmax(T1 &x, const T2 &y) {
    if (x < y) {
        x = y;
        return 1;
    }
    else {
        return 0;
    }
}

#define all(c) (c).begin(), (c).end()
#define sz(c) (int)(c).size()
#define mp make_pair
#define pb push_back
#define read(FILENAME) freopen((string(FILENAME) + ".in").c_str(), "r", stdin)
#define write(FILENAME) freopen((string(FILENAME) + ".out").c_str(), "w", stdout);

template<class iterator> void output(iterator begin, iterator end, ostream &out = cerr) {
    while (begin != end) {
        out << (*begin) << " ";
        begin++;
    }
    out << endl;
}


template<class T> void output(const T &x, ostream &out = cerr) {
    output(x.begin(), x.end(), out);
}

void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0); 
}
const int MAXN = 3005;


struct point
{
    int x, y, w;
    point(){}
    point(int _x, int _y) {
        x = _x;
        y = _y;
    }
};


bool operator <(const point &a, const point &b) {
    return a.x < b.x || (a.x == b.x && a.y < b.y);
}


point operator -(const point &a, const point &b) {
    return point(a.x - b.x, a.y - b.y);
}


long long vec(const point &a, const point &b) {
    return 1LL * a.x * b.y - 1LL * a.y * b.x;
}


int n;
point p[MAXN];
int pos[MAXN];


long long comp(pair<int, int> a, pair<int, int> b) {
    point g = p[a.second] - p[a.first];
    point g1 = p[b.second] - p[b.first];
    return vec(g, g1);
}


long long comp1(pair<int, int> a, pair<int, int> b) {
    long long ft = comp(a, b);
    if (ft != 0) {
        return ft < 0;
    } else {
        return a < b;
    }
}


struct node {
    long long sum, pref, suf, val;
    node(int x = 0) {
      sum = (long long) x;
      pref = suf = val = (long long)max(x, 0);
    };
   friend node operator + (const node &l, const node &r) {
        node ans;
        ans.sum = l.sum + r.sum;
        ans.pref = max(l.pref, l.sum + r.pref);
        ans.suf = max(r.suf, r.sum + l.suf);
        ans.val = max({l.val, r.val, l.suf + r.pref});
        return ans;
   }
};
 

node t[MAXN * 2]; 

 
void modify(int v, int l, int r, int pos, int val) {
    if (l == r) {
        t[v] = node(val);
        return;
    }
    int mid = (l + r) >> 1;
    if (pos <= mid) {
        modify(v << 1, l, mid, pos, val);
    } else {
        modify(v << 1 | 1, mid + 1, r, pos, val);
    }
    t[v] = t[v << 1] + t[v << 1 | 1];
}

int main() {
    fast_io();
    //read("input");
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> p[i].x >> p[i].y >> p[i].w;  
    }
    sort(p + 1, p + n + 1);
    vector<pair<int, int> > st;
    for (int i = 1; i <= n; i++) {
        for (int j = i + 1; j <= n; j++) {
            st.pb({i, j});
        }
    }
    sort(all(st), comp1);
    for (int i = 1; i <= n; i++) {
        pos[i] = i;
        modify(1, 1, n, i, p[i].w);
    }
    long long ans = t[1].val;
    for (int i = 0; i < sz(st); i++)  {
        vector<pair<int, int> > kek;
        kek.pb(st[i]);
        int j = i + 1;
        while (j < sz(st) && !comp(st[j - 1], st[j])) {
            kek.pb(st[j]);
            j++;
        }
        for (auto x: kek) {
            int a = x.first;
            int b = x.second;
            swap(pos[a], pos[b]);
            modify(1, 1, n, pos[a], p[a].w);
            modify(1, 1, n, pos[b], p[b].w);
        }
        chkmax(ans, t[1].val);
    }
    cout << ans << '\n';
    return 0;
}   

• Subtask 1: 0 / 5
• Subtask 2: 20 / 20
• Subtask 3: 35 / 35
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20