oj.uz

답안 #227660

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
227660 2020-04-28T10:16:50 Z nafis_shifat Building Bridges (CEOI17_building) C++14
60 / 100
 187 ms 5608 KB 
#include<bits/stdc++.h>
#define pii pair<int,int>
#define ll long long
using namespace std;
const int mxn=1e5+7;
vector<ll> m;
vector<ll> b;

ll h[mxn];
ll w[mxn];
ll p[mxn];

ll dp[mxn];

bool bad(int f1,int f2,int f3)
{
	return (b[f3]-b[f1])*(m[f1]-m[f2])<=(b[f2]-b[f1])*(m[f1]-m[f3]);
}

void add(ll m_,ll b_)
{       
	m.push_back(m_);
	b.push_back(b_);
	int sz=m.size();
	while(sz>=3 && bad(sz-3,sz-2,sz-1))
	{
		m.erase(m.end()-2);
		b.erase(b.end()-2);
		sz--;
	}
}

ll func(int p,ll x)
{
	return m[p]*x+b[p];
}
ll query(ll x)
{
    ll ans=1e18;
    int lo=0;
    int hi=m.size()-1;
    while(lo<=hi)
    {
     	int mid1=lo+(hi-lo)/3;
        int mid2=hi-(hi-lo)/3;
        if(func(mid1,x)<func(mid2,x))
        {
            ans=min(ans,func(mid1,x));
            hi=mid2-1;
        }
        else
        {
            ans=min(ans,func(mid2,x));
            lo=mid1+1;
        }
    }
    return ans;
}
     
void solve(int l,int r)
{
	if(l==r)return;
	int mid=l+r>>1;
	solve(l,mid);
	vector<int> v;
	for(int i=l;i<=mid;i++)v.push_back(i);
    m.clear();
    b.clear();
	sort(v.begin(),v.end(),[](int a,int b)
	{
		return h[a]<h[b];
	});

    for(int i=0;i<v.size();i++)
    {
        
    	int k=v[i];
    	add(-2*h[k],dp[k]+h[k]*h[k]-p[k]);
    }

    for(int i=mid+1;i<=r;i++)
    {
    	dp[i]=min(dp[i],query(h[i])+h[i]*h[i]+p[i-1]);
    }

    
    solve(mid+1,r);
    

}


int main()
{
    for(int i=1;i<mxn;i++)dp[i]=1e18;
    dp[1]=0;
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)scanf("%lld",&h[i]);
	p[0]=0;
	for(int i=1;i<=n;i++)
	{
		scanf("%lld",&w[i]);
		p[i]=p[i-1]+w[i];
	}

	solve(1,n);

	cout<<dp[n]<<endl;
	return 0;
}

Compilation message

building.cpp: In function 'void solve(int, int)':
building.cpp:63:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=l+r>>1;
          ~^~
building.cpp:74:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<v.size();i++)
                 ~^~~~~~~~~
building.cpp: In function 'int main()':
building.cpp:99:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n;i++)scanf("%lld",&h[i]);
                       ~~~~~^~~~~~~~~~~~~~
building.cpp:103:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld",&w[i]);
   ~~~~~^~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 1152 KB Output is correct
2 Correct 5 ms 1024 KB Output is correct
3 Correct 5 ms 1152 KB Output is correct
4 Correct 6 ms 1152 KB Output is correct
5 Correct 6 ms 1152 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 184 ms 3952 KB Output is correct
2 Correct 187 ms 5044 KB Output is correct
3 Correct 183 ms 4852 KB Output is correct
4 Correct 173 ms 4836 KB Output is correct
5 Correct 124 ms 5416 KB Output is correct

Subtask #3
0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 1152 KB Output is correct
2 Correct 5 ms 1024 KB Output is correct
3 Correct 5 ms 1152 KB Output is correct
4 Correct 6 ms 1152 KB Output is correct
5 Correct 6 ms 1152 KB Output is correct
6 Correct 184 ms 3952 KB Output is correct
7 Correct 187 ms 5044 KB Output is correct
8 Correct 183 ms 4852 KB Output is correct
9 Correct 173 ms 4836 KB Output is correct
10 Correct 124 ms 5416 KB Output is correct
11 Correct 178 ms 5132 KB Output is correct
12 Correct 184 ms 4976 KB Output is correct
13 Correct 141 ms 5052 KB Output is correct
14 Correct 185 ms 5160 KB Output is correct
15 Correct 111 ms 5608 KB Output is correct
16 Correct 115 ms 5240 KB Output is correct
17 Correct 71 ms 5056 KB Output is correct
18 Incorrect 77 ms 5056 KB Output isn't correct