Submission #89845

#	Time	Username	Problem	Language	Result	Execution time	Memory
89845		giorgikob	Building Bridges (CEOI17_building)	C++14	0 / 100	2 ms	512 KiB

building

#include<bits/stdc++.h>
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define mod 1000000007
#define ll long long
using namespace std;
ll n, m, k, x, y, a, b, t, q, ans;

ll W[500001],H[500001],dp[500001],sum[500001],DP[500001],B[500001];
struct tree{
	tree* L;
	tree* R;
	ll k,b;
	tree(){
		k=b=0LL;
		L=R=NULL;
	}
};
tree* root=new tree();
double cross(double k,double b,double K,double B){
	//if(K-k==0)cout<<1<<endl;
	return (b-B)/(K-k);
}
void update(tree* node,ll l,ll r,ll K,ll B){
	ll K1=node->k;
	ll B1=node->b;
	if(K1==0 && B1==0){
		node->k=K;
		node->b=B;
		return ;
	}
	if(K1==K){
		if(B<B1){
			node->k=K;
			node->b=B;
		}
		return ;
	}
	double x=cross(K1,B1,K,B);
	ll y=x-10;
	bool ok=( y*K+B < y*K1+B1 );
	
	
	if(ok){
		if(x<l)return;
		if(x>r){
			node->k=K;
			node->b=B;
			return ;	
		}
		if(l==r)return ;
		ll mid=(l+r)/2;
		if(x<=mid) {
			if(node->L == NULL)
				node->L = new tree();
			update(node->L,l,mid,K,B);
		} else 
		if(x>mid) {
			if(node->R == NULL)
				node->R = new tree();
			node->k=K;
			node->b=B;
			update(node->R,mid+1,r,K1,B1);
		}
	} else {
		if(x>r)return;
		if(x<l){
			node->k=K;
			node->b=B;
			return ;	
		}
		if(l==r)return ;
		ll mid=(l+r)/2;
		if(x>mid) {
			if(node->R == NULL)
				node->R = new tree();
			update(node->R,mid+1,r,K,B);
		} else 
		if(x<=mid) {
			if(node->L == NULL)
				node->L = new tree();
			node->k=K;
			node->b=B;
			update(node->L,l,mid,K1,B1);
		}	
	}
}
ll get(tree* node,ll l,ll r,ll x){
	if(l==r)
		return node->k*x+node->b;
	ll mid=(l+r)/2;
	if(x<=mid){
		if(node->L==NULL)
			return node->k*x+node->b;
		else{
			ll y=get(node->L,l,mid,x);
			return min(y,node->k*x+node->b);		
		}
	} else {
		if(node->R==NULL)
			return node->k*x+node->b;
		else{
			ll y=get(node->R,mid+1,r,x);
			return min(y,node->k*x+node->b);
		}
	}	
}
main()
{
	//ios::sync_with_stdio(0);
	freopen("a.in","r",stdin);
	cin>>n;
	for(int i=1;i<=n;i++)
		cin>>H[i];
	
	for(int i=1;i<=n;i++)
		cin>>W[i],sum[i]=sum[i-1]+W[i];
	
	update(root,0LL,1e10,-2*H[1],H[1]*H[1]-sum[1]);
	for(int i=2;i<=n;i++){
		dp[i]=H[i]*H[i]+sum[i-1]+get(root,0LL,1e10,H[i]);
		//cout<<get(root,0,1e6,H[i])<<" ";
		update(root,0LL,1e10,-2*H[i],H[i]*H[i]+dp[i]-sum[i]);
		//cout<<dp[i]<<endl;
	}
	
	/*for(int i=2;i<=n;i++){
		DP[i]=1e18;
		for(int j=1;j<i;j++){
			DP[i]=min(DP[i],H[i]*H[i]+sum[i-1]-2*H[i]*H[j]+H[j]*H[j]+DP[j]-sum[j]);
		}
		for(int j=1;j<i;j++){
			if(DP[i]==H[i]*H[i]+sum[i-1]-2*H[i]*H[j]+H[j]*H[j]+DP[j]-sum[j])
			B[i]=j;
		}
	}
	
	for(int i=1;i<=n;i++)
	if(DP[i]!=dp[i])
	cout<<DP[i]<<" "<<dp[i]<<" "<<i<<" "<<B[i]<<endl;*/
	
	cout<<dp[n]<<endl;
}
/*
6
3 8 7 1 6 6
0 -1 9 1 2 0

20
587 7874 8557 8774 4337 4840 753 8130 8169 8291  1265 2647 7412 7414 7784 3118 4177 5906 6764 7214 
587 7874 8557 8774 4337 4840 753 8130 8169 8291  1265 2647 7412 7414 7784 3118 4177 5906 6764 7214
*/

Compilation message (stderr)

building.cpp:110:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^
building.cpp: In function 'int main()':
building.cpp:113:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  freopen("a.in","r",stdin);
  ~~~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40