#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define fst first
#define snd second
#define int long long
#define fast_io() ios::sync_with_stdio(false)
#define FOR(i, l, r) for(int i = (l); i < (r); i++)
typedef long long ll;
typedef pair<ll, ll> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef set<int> si;
typedef double ld;
typedef pair<ld, ld> dd;
const ll INF = 1000000000000000000LL;
const int NMAX = 1e6+4;
const int mod = 1e9+7;
const ld eps = 1e-10;
const ld PI = acos(-1);
struct point{
int x, y, w, i;
const bool operator< (const point &p){
return mp(x, y) < mp(p.x, p.y);
}
};
int N;
vector<point> pts;
vi position;
struct event{
int i, j;
int dx, dy;
event(int a, int b) : i(a), j(b) {
if(pts[j].x < pts[i].x) swap(i, j);
dx = pts[j].x - pts[i].x;
dy = pts[j].y - pts[i].y;
}
event(){}
friend bool operator< ( const event &e1, const event &e2){
int s = e1.dy * e2.dx - e2.dy * e1.dx;
if(s != 0) return s < 0;
return e1.dx * (pts[position[e1.i]].y - pts[position[e2.i]].y) + e1.dy * (pts[position[e2.i]].x - pts[position[e1.i]].x) < 0;
}
};
bool par(const event &e1, const event &e2){
return e1.dy * e2.dx == e2.dy * e1.dx;
}
bool col(const event &e1, const event &e2){
return !(e1 < e2) and !(e2 < e1);
}
vi tsum, tmin, tmax, tbest;
void update(int n){
int l = n<<1, r = l|1;
tsum[n] = tsum[l] + tsum[r];
tmin[n] = min(tmin[l], tsum[l] + tmin[r]);
tmax[n] = max(tmax[l], tsum[l] + tmax[r]);
tbest[n] = max(tsum[l] + tmax[r] - tmin[l], max(tbest[l], tbest[r]));
}
void buildtree(int lb, int rb, int n = 1){
if(lb+1 == rb) {
int w = pts[lb].w;
tsum[n] = w;
tmin[n] = min(0LL, w);
tbest[n] = tmax[n] = max(0LL, w);
} else {
int mb = (lb+rb)/2;
buildtree(lb, mb, n<<1);
buildtree(mb, rb, n<<1|1);
update(n);
}
}
void modify(int i, int w, int lb, int rb, int n = 1){
if(lb+1 == rb){
tsum[n] = w;
tmin[n] = min(0LL, w);
tmax[n] = max(0LL, w);
} else {
int mb = (lb+rb)/2;
if(i < mb) modify(i, w, lb, mb, n<<1);
else modify(i, w, mb, rb, n<<1|1);
update(n);
}
}
int getbest(){
return tbest[1];
}
vector<event> events;
signed main(){
fast_io();
cin >> N;
tmin.assign(4*N, 0);
tmax.assign(4*N, 0);
tsum.assign(4*N, 0);
tbest.assign(4*N, 0);
position.assign(N, 0);
FOR(i, 0, N){
int x,y,w;
cin >> x >> y >> w;
pts.pb({x, y, w, y});
}
sort(pts.begin(), pts.end());
FOR(i, 0, N) pts[i].i = i;
FOR(i, 0, N) position[pts[i].i] = i;
buildtree(0, N);
FOR(i, 0, N) FOR(j, i+1, N) events.pb(event(i, j));
//sort(events.begin(), events.end());
// each block contains parallel events
//cout << "Sorted events" << endl;
vector<vector<vector<event>>> blocks;
FOR(i, 0, events.size()){
if(i == 0 || !par(events[i], events[i-1])) blocks.pb( vector<vector<event>>(0));
if(i == 0 || !col(events[i], events[i-1])) blocks.back().pb(vector<event>(0));
blocks.back().back().pb(events[i]);
}
int best = getbest();
for( auto pars : blocks) {
// cout << "pars size " << pars.size() << endl;
for(auto cols : pars){
//cout << "cols size " << cols.size() << endl;
int l = N, r = 0;
for(event e : cols) l = min(l, position[e.i]), l = min(l, position[e.j]), r = max(r, position[e.i]), r = max(r, position[e.j]);
// swap [l, r]
//cout << "swapping " << l << " " << r << endl;
for(int i = l, j = r; i < j; i++, j--){
// positions in
int p1 = pts[i].i, p2 = pts[j].i;
swap(position[p1], position[p2]);
int w1 = pts[i].w, w2 = pts[j].w;
modify(i, w2, 0, N);
modify(j, w1, 0, N);
swap(pts[i], pts[j]);
}
}
best = max(best, getbest());
}
cout << best << endl;
}
/*
5
-5 5 -2
2 5 10
1 4 -2
4 -5 4
-2 2 7
*/
Compilation message
bulldozer.cpp: In function 'int main()':
bulldozer.cpp:10:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
#define FOR(i, l, r) for(int i = (l); i < (r); i++)
^
bulldozer.cpp:131:5: note: in expansion of macro 'FOR'
FOR(i, 0, events.size()){
^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 2 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 3 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 4 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 5 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 6 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 7 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 8 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 9 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 10 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 11 |
Correct |
2 ms |
256 KB |
Output is correct |
| 12 |
Correct |
2 ms |
384 KB |
Output is correct |
| 13 |
Correct |
3 ms |
384 KB |
Output is correct |
| 14 |
Correct |
2 ms |
384 KB |
Output is correct |
| 15 |
Correct |
2 ms |
384 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
5 ms |
1000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
5 ms |
1000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
5 ms |
1000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 2 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 3 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 4 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 5 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 6 |
Correct |
2 ms |
1152 KB |
Output is correct |
| 7 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 8 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 9 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 10 |
Correct |
3 ms |
1152 KB |
Output is correct |
| 11 |
Correct |
2 ms |
256 KB |
Output is correct |
| 12 |
Correct |
2 ms |
384 KB |
Output is correct |
| 13 |
Correct |
3 ms |
384 KB |
Output is correct |
| 14 |
Correct |
2 ms |
384 KB |
Output is correct |
| 15 |
Correct |
2 ms |
384 KB |
Output is correct |
| 16 |
Incorrect |
5 ms |
1000 KB |
Output isn't correct |
| 17 |
Halted |
0 ms |
0 KB |
- |
