Submission #1066607

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066607		vjudge1	Building Bridges (CEOI17_building)	C++17	30 / 100	3065 ms	17624 KiB

building

#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pu push_back
#define ll long long
typedef pair <ll,ll> ii;
const int N=1e6;
long long mod=1e9;
long n,m,k;
long a[N+1],g[N+10];
ll dp[N+1];
ii b[N+10];
struct line{
    long a,b,id;
    };
line l[N+1],s[N+1],S[N+1];
double e[N+1];
bool cmp(line A,line B){
    if(A.a!=B.a) return A.a>B.a;
    else return A.b>B.b;
    }
bool ok(long i){
    if(l[i].a==s[k].a) return true;
    if(k==1) return false;
    double x1,x2;
    x1=1.0*(l[i].b-s[k-1].b)/(s[k-1].a-l[i].a);
    x2=1.0*(s[k].b-s[k-1].b)/(s[k-1].a-s[k].a);
    return x1<=x2;
    }
void tinh(){
    cin>>n;
    for(long i=1;i<=n;i++) {cin>>b[i].fi;}
    for(int i=1;i<=n;i++) cin>>b[i].se;
    g[n+1]=0;
    for(int i=n;i>=1;i--) {g[i]=g[i+1]+b[i].se;
    }
    k=1;
    /*
    6
    3 8 7 1 6 6
    0 -1 9 1 2 0
    */
    l[1].b=b[1].fi*b[1].fi+g[2];
    l[1].id=1;
    l[1].a=-2*b[1].fi;
    e[1]=1.0*1e18;
    s[1]=l[1];
    S[1]=l[1];

    dp[1]=0;
    for(long i=2;i<=n;i++){
        long A=-2*b[i].fi,B=0;

        ll res=mod;
        for(int x=1;x<i;x++)
        res=min(res,l[x].b + l[x].a*b[i].fi + b[i].fi*b[i].fi - g[i]);
        dp[i]=res;
        B=dp[i]+g[i+1]+b[i].fi*b[i].fi;
        l[i].a=A;
        l[i].b=B;
        l[i].id=i;
        if(l[i].a==s[k].a and l[i].b>=s[k].b) continue;
        while(k>0 and ok(i)) k--;
        k++;
        s[k]=l[i];
        e[k-1]=1.0*(s[k-1].b-s[k].b)/(s[k].a-s[k-1].a);
        e[k]=1.0*1e18;
     }
    cout<<dp[n];
    }
int main(){
    //freopen("jday.inp","r",stdin);
    //freopen("jday.out","w",stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    tinh();
    return 0;

}
//code của anh Nam đẹp trai nhất CHL

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