oj.uz

Submission #63156

# Submission time Handle Problem Language Result Execution time Memory
63156 2018-08-01T01:28:59 Z khsoo01 Building Bridges (CEOI17_building) C++11
100 / 100
 206 ms 17336 KB 
#include<bits/stdc++.h>
#define X first
#define Y second
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;
const ll N = 100005, L = 18, inf = 1e18;

ll n, def, h[N], a[N], d[N];

ll val (pll &P, ll V) {return P.X*V+P.Y;}

bool valid (pll &A, pll &B, pll &C) {
	return (B.Y-A.Y) * (B.X-C.X)  < (C.Y-B.Y) * (A.X-B.X);
}

struct hull {
	vector<pll> v;
	void upd (pll P) {
		for(ll i=v.size();i--;) {
			if(v[i].X != P.X) break;
			else v.pop_back();
		}
		for(ll i=v.size();i-->1;) {
			if(valid(v[i-1], v[i], P)) break;
			else v.pop_back();
		}
		v.push_back(P);
	}
	ll get (ll P) {
		if(v.empty()) return inf;
		ll S = 0, E = (int)v.size()-1;
		while(S<E) {
			ll M = (S+E)/2;
			val(v[M], P) < val(v[M+1], P) ? E = M : S = M+1;
		}
		return val(v[S], P);
	}
} x[L];

void Merge (hull &A, hull &B) {
	vector<pll> V;
	for(int i=0,j=0;i<A.v.size()||j<B.v.size();) {
		bool flag = false;
		if(i == A.v.size()) flag = true;
		else if(j == B.v.size()) flag = false;
		else if(A.v[i] < B.v[j]) flag = true;
		if(flag) {V.push_back(B.v[j]); j++;}
		else {V.push_back(A.v[i]); i++;}
	}
	A.v.clear(); B.v.clear();
	for(auto &T : V) A.upd(T);
}

int main()
{
	scanf("%lld",&n);
	for(ll i=1;i<=n;i++) scanf("%lld",&h[i]);
	for(ll i=1;i<=n;i++) {scanf("%lld",&a[i]); def += a[i];}
	x[0].upd(pll(-2*h[1], h[1]*h[1]-a[1]));
	for(ll i=2;i<=n;i++) {
		d[i] = inf;
		for(ll j=0;j<L;j++) {
			d[i] = min(d[i], x[j].get(h[i])-a[i]+h[i]*h[i]);
		}
		hull tmp;
		tmp.upd(pll(-2*h[i], h[i]*h[i]+d[i]));
		for(ll j=0;j<L;j++) {
			if(x[j].v.empty()) {swap(x[j], tmp); break;}
			else Merge(tmp, x[j]);
		}
	}
	printf("%lld\n",d[n]+def);
}

Compilation message

building.cpp: In function 'void Merge(hull&, hull&)':
building.cpp:43:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0,j=0;i<A.v.size()||j<B.v.size();) {
                  ~^~~~~~~~~~~
building.cpp:43:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0,j=0;i<A.v.size()||j<B.v.size();) {
                                ~^~~~~~~~~~~
building.cpp:45:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(i == A.v.size()) flag = true;
      ~~^~~~~~~~~~~~~
building.cpp:46:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   else if(j == B.v.size()) flag = false;
           ~~^~~~~~~~~~~~~
building.cpp: In function 'int main()':
building.cpp:57:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld",&n);
  ~~~~~^~~~~~~~~~~
building.cpp:58:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(ll i=1;i<=n;i++) scanf("%lld",&h[i]);
                       ~~~~~^~~~~~~~~~~~~~
building.cpp:59:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(ll i=1;i<=n;i++) {scanf("%lld",&a[i]); def += a[i];}
                        ~~~~~^~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 496 KB Output is correct
3 Correct 2 ms 496 KB Output is correct
4 Correct 4 ms 532 KB Output is correct
5 Correct 4 ms 628 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 183 ms 4436 KB Output is correct
2 Correct 160 ms 5404 KB Output is correct
3 Correct 206 ms 6600 KB Output is correct
4 Correct 158 ms 7240 KB Output is correct
5 Correct 95 ms 9880 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 496 KB Output is correct
3 Correct 2 ms 496 KB Output is correct
4 Correct 4 ms 532 KB Output is correct
5 Correct 4 ms 628 KB Output is correct
6 Correct 183 ms 4436 KB Output is correct
7 Correct 160 ms 5404 KB Output is correct
8 Correct 206 ms 6600 KB Output is correct
9 Correct 158 ms 7240 KB Output is correct
10 Correct 95 ms 9880 KB Output is correct
11 Correct 164 ms 9880 KB Output is correct
12 Correct 151 ms 10516 KB Output is correct
13 Correct 94 ms 11288 KB Output is correct
14 Correct 201 ms 12736 KB Output is correct
15 Correct 117 ms 17336 KB Output is correct
16 Correct 93 ms 17336 KB Output is correct
17 Correct 54 ms 17336 KB Output is correct
18 Correct 52 ms 17336 KB Output is correct