Submission #942546

#	Time	Username	Problem	Language	Result	Execution time	Memory
942546		qin	Bulldozer (JOI17_bulldozer)	C++17	5 / 100	2 ms	860 KiB

bulldozer

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define fi first
#define se second
#define pn printf("\n")
#define ssize(x) int(x.size())
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define bitcount(x) __builtin_popcount(x)
#define clz(x) __builtin_clz(x)
#define ctz(x) __builtin_ctz(x)
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<int, ll> pil;
typedef pair<ll, int> pli;
typedef pair<ll, ll> pll;
typedef double db;
typedef long double ldb;
#define vv vector
/*void read(int &a){
		char c = getchar_unlocked(); a = 0;
		while(c<'0' || '9'<c) c = getchar_unlocked();
		while('0'<=c&&c<='9') a = (a<<3)+(a<<1)+c-'0', c = getchar_unlocked();
}*/
int inf = 2e09; ll infll = 2e18; int mod = (1<<23)*119+1;
struct pt{
		int x, y, val;
		pt(){ x = 0, y = 0, val = 0; }
		pt(int X, int Y, int V){ x = X, y = Y, val = V; }
		bool operator <(const pt &a) const{ return x != a.x ? x < a.x : y < a.y; }
};
double eps = 1e-9;
bool equal(db a, db b){ return abs(b-a) < eps; }
struct line{
		db a, b;
		int x1, x2, i, j;
		line(){ a = 0, b = 0, x1 = 0, x2 = 0, i = 0, j = 0; }
		line(int X1, int Y1, int X2, int Y2, int I, int J){
				if(X1 == X2) a = INT_MAX, b = 0, x1 = min(Y1, Y2), x2 = max(Y1, Y2);
				else a = (Y2-Y1)/db(X2-X1), b = db(Y1)-a*X1, x1 = min(X1, X2), x2 = max(X1, X2);
				i = I, j = J;
		}
		bool operator <(const line &t) const{
				if(!equal(a, t.a)) return a < t.a;
				else if(!equal(b, t.b)) return b < t.b;
				else if(!equal(x1, t.x1)) return x1 < t.x1;
				return x2 < t.x2;
		}
};
int base = 1;
struct seg{
		struct Node{
				ll mx, mn, mx_delta;
				Node(){ mx = -infll, mn = infll, mx_delta = -infll; }
				Node(ll val){ mx = val, mn = val, mx_delta = 0; }
		};
		vv<Node> t;
		void init(int n, vv<ll> &pf){
				while(base < n) base <<= 1;
				t.resize(base<<1);
				for(int i = 1; i <= n; ++i) t[i+base-1] = Node(pf[i]);
				for(int i = base-1; i; --i){
						t[i].mx = max(t[i<<1].mx, t[i<<1|1].mx);
						t[i].mn = min(t[i<<1].mn, t[i<<1|1].mn);
						t[i].mx_delta = max(t[i<<1|1].mx-t[i<<1].mn, max(t[i<<1].mx_delta, t[i<<1|1].mx_delta));
				}
		}
		void update(int i, ll val){ //tutaj ewentualnie mozna dozylolwywac
				for(i += base-1, t[i] = Node(val), i >>= 1; i; i >>= 1){
						t[i].mx = max(t[i<<1].mx, t[i<<1|1].mx);
						t[i].mn = min(t[i<<1].mn, t[i<<1|1].mn);
						t[i].mx_delta = max(t[i<<1|1].mx-t[i<<1].mn, max(t[i<<1].mx_delta, t[i<<1|1].mx_delta));
				}
		}
		ll query(){ return max(t[1].mx, t[1].mx_delta); }
};
void answer(){
		int n; scanf("%d", &n);
		vv<pt> p(n+1);
		for(int i = 1; i <= n; ++i) scanf("%d%d%d", &p[i].x, &p[i].y, &p[i].val);
		sort(1+all(p));
		vv<line> t((n*(n-1))/2);
		for(int i = 1, l = 0; i <= n-1; ++i)
				for(int j = i+1; j <= n; ++j, ++l) t[l] = line(p[i].x, p[i].y, p[j].x, p[j].y, i, j);
		sort(all(t));
		//~ for(line &u : t) printf("%f %f %d %d\n", u.a, u.b, u.x1, u.x2);
		
		vv<ll> pf(n+1);
		vv<int> pos(n+1);
		for(int i = 1; i <= n; ++i) pf[i] = pf[i-1]+p[i].val, pos[i] = i;
		seg seg; seg.init(n, pf);
		
		
		ll result = max(0ll, seg.query());
		//~ printf("%lld\n", result);
		//~ for(int i = 1; i <= n; ++i) printf("%lld ", pf[i]);
		//~ pn;
		for(int i = 0; i < ssize(t); ++i){
				int a = t[i].i, b = t[i].j; assert(abs(pos[a]-pos[b]) == 1);
				if(pos[b] < pos[a]) swap(a, b);
				pf[pos[a]] += p[b].val-p[a].val;
				swap(pos[a], pos[b]);
				seg.update(pos[a], pf[pos[a]]), seg.update(pos[b], pf[pos[b]]);
				
				while(i+1 < ssize(t) && equal(t[i+1].a, t[i].a)){
						++i;
						a = t[i].i, b = t[i].j; assert(abs(pos[a]-pos[b]) == 1);
						if(pos[b] < pos[a]) swap(a, b);
						pf[pos[a]] += p[b].val-p[a].val;
						swap(pos[a], pos[b]);
						seg.update(pos[a], pf[pos[a]]), seg.update(pos[b], pf[pos[b]]);
				}
				result = max(result, seg.query());
				//~ printf("%lld\n", seg.query());
				//~ for(int j = 1; j <= n; ++j) printf("%lld ", pf[j]);
				//~ pn;
		}
		printf("%lld\n", result);
}
signed main(){
		int T = 1;
		//~ scanf("%d", &T);
		//~ ios_base::sync_with_stdio(0); cin.tie(0); //cin >> T;
		for(++T; --T; ) answer();
		return 0;
}

Compilation message (stderr)

bulldozer.cpp: In function 'void answer()':
bulldozer.cpp:79:15: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |   int n; scanf("%d", &n);
      |          ~~~~~^~~~~~~~~~
bulldozer.cpp:81:36: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |   for(int i = 1; i <= n; ++i) scanf("%d%d%d", &p[i].x, &p[i].y, &p[i].val);
      |                               ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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