Submission #1270268

#	Time	Username	Problem	Language	Result	Execution time	Memory
1270268		luattapcode	Building Bridges (CEOI17_building)	C++20	30 / 100	14 ms	9028 KiB

building

/*The best way to get something done is to begin*/
#include     <bits/stdc++.h>
#define     ll long long
#define     int long long
#define     fr(i,a,b) for(int i=a;i<=b;i++)
#define     frd(i,a,b) for(int i=a;i>=b;i--)
#define     pb push_back
#define     fi first
#define     se second
#define     el '\n'
using namespace std;
template <class X, class Y> bool minimize(X &x, const Y &y) {if (x > y) {x = y;return true;} else return false;}
template <class X, class Y> bool maximize(X &x, const Y &y) {if (x < y) {x = y;return true;} else return false;}
/* Author: Huynh Quoc Luat */
/*Khai Bao*/
const long long inf=1e18;
const int oo=1e9;
const int LO=21;
const int CH=27;
const int N=1e5+5;
const int sm=1e9+7;
int n;
int h[N],w[N];
//void add(int &x,const int &y){x+=y;if(x>=sm)x-=sm;}
//void sub(int &x,const int &y){x-=y;if(x<0)x+=sm;}

void read()
{
    cin >> n;
    fr(i,1,n) cin >> h[i];
    fr(i,1,n) cin >> w[i];
}   

namespace sub1
{
    int s[N];
    const int N=1005;
    int dp[N];
    int cost(int i,int j){
        return (h[i]-h[j])*(h[i]-h[j]);
    }
    void process()
    {
        fr(i,1,n) s[i]=s[i-1]+w[i];
        memset(dp,0x3f,sizeof dp);
        dp[1]=0;
        fr(i,2,n){
            fr(j,1,i-1){
                minimize(dp[i],dp[j]+cost(i,j)+s[i-1]-s[j]);
            }
        }
        cout << dp[n];
    }
}

namespace sub2
{
    int dp[N];
   struct Line
    {
        ll a, b;
        Line() {a = 0, b = inf;}
        Line(ll _a, ll _b) {a = _a, b = _b;}
        ll operator()(ll x) {return 1ll * a * x + b;}
    } st[4 * N];
    int s[N];
    void upd(int id, int l, int r, Line L)
    {
        if(l == r) {
            if(st[id](l) > L(l)) swap(st[id], L);
            return;
        }
        int mid = (r + l) >> 1;
        if(st[id].a > L.a) swap(st[id], L);
        if(st[id](mid) > L(mid)) {
            swap(st[id], L);
            upd(id << 1 | 1, mid + 1, r, L);
        }
        else upd(id << 1, l, mid, L);
    }
    ll get(int id, int l, int r, int pos)
    {
        if(l == r) return st[id](pos);
        int mid = (r + l) >> 1;
        if(pos <= mid) return min(st[id](pos), get(id << 1, l, mid, pos));
        else return min(st[id](pos), get(id << 1 | 1, mid + 1, r, pos));
    }
    void process(){
        fr(i,1,n) s[i]=s[i-1]+w[i];
        upd(1,0,1e6,Line(-2*h[1],dp[1]+h[1]*h[1]+s[1]));
        fr(i,2,n){
            dp[i]=h[i]*h[i]+s[i-1]+get(1,0,1e6,h[i]);
            upd(1,0,1e6,Line(-2*h[i],dp[i]+h[i]*h[i]+s[i]));
        }
        cout << dp[n];
    }
}
void time()    {cerr<< endl<<"Luattapcode: "<<clock()<<"ms"<<endl;}
main()
{
    ios_base::sync_with_stdio(NULL);cin.tie(NULL);cout.tie(NULL);
    #define TASK "qn"
    if(fopen(TASK".INP","r"))
    {
        freopen(TASK".INP", "r", stdin);
        freopen(TASK".OUT", "w", stdout);
    }
    int mtt=0;
    int test=1;
    if(mtt) cin>>test;
    while(test--)
    {
        read();
        if(n<=1000) sub1::process();
        else sub2::process();
    }
    time();
    return 0;
}

Compilation message (stderr)

building.cpp:99:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   99 | main()
      | ^~~~
building.cpp: In function 'int main()':
building.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen(TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
building.cpp:106:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |         freopen(TASK".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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