Submission #476248

#	Time	Username	Problem	Language	Result	Execution time	Memory
476248		LptN21	Building Bridges (CEOI17_building)	C++14	30 / 100	50 ms	3588 KiB

building

#include <bits/stdc++.h>
using namespace std;
#define fastIO ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL)
#define PI acos(-1.0)
#define FF first
#define SS second
#define eps 1e-9
// vector
#define pb push_back
#define sz(v) int((v).size())
#define all(v) (v).begin(), (v).end()
#define lb lower_bound
#define ub upper_bound
// bit
#define CNTBIT(x) __builtin_popcount(x)
#define ODDBIT(x) __builtin_parity(x)
#define MASK(i) (1ll<<(i))
#define BIT(x, i) (((x)>>(i))&1)
#define SUBSET(big, small) (((big)&(small))==(small))
#define MINBIT(x) (x)&(-x)
// typedef
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> ii;
typedef pair<int, ii> i3;
/* CODE BELOW */
const int N=1e6+7, M=1e5+7;
const int MOD=1e9+7;
const ll oo=1e9+9;

int n, m, k, t;

int a[M], p[M];
ll _dp[M];

struct node
{
     ll x, y;
     node(){}
     node(ll x, ll y): x(x), y(y){};
     ll get(ll t)
     {
         return x * t + y;
     }
}st[N*4];
void add(ll id, ll l, ll r, node d)
{
    ll mid = (l + r) / 2;
    bool ok1 = d.get(mid) < st[id].get(mid);
    bool ok2 = d.get(l) < st[id].get(l);
    if(ok1)swap(st[id], d);
    if(l+1 == r)return;
    if(ok1 != ok2)add(id*2, l, mid, d);
    else add(id*2+1, mid, r, d);
}
ll query(ll id, ll l, ll r, ll x)
{
    ll mid = (l + r) / 2;
    ll res = st[id].get(x);
    if(l+1 == r)return res;
    if(x < mid)return min(res, query(id*2, l, mid, x));
    else return min(res, query(id*2+1, mid, r, x));
}

signed main() {
    //freopen("test.inp", "r", stdin);
    //freopen("test.out", "w", stdout);
    //fastIO;
    scanf("%d", &n);
    for(int i=1;i<=n;i++) scanf("%d", &a[i]);
    for(int i=1;i<=n;i++) {
        scanf("%d", &m);
        p[i]=p[i-1]+m;
    }

    _dp[1]=0;
    const int SUB1=1000;
    #define sqr(x) 1LL*(x)*(x)

    if(n<=SUB1) {
        for(int i=2;i<=n;i++) {
            _dp[i]=oo;
            for(int j=i-1;j>0;j--) {
                ll cost=sqr(a[i]-a[j])+p[i-1]-p[j];
                _dp[i]=min(_dp[i], _dp[j]+cost);
            }
        }
        printf("%lld", _dp[n]);
    } else {
        add(1, 1, N, {-2*a[1], sqr(a[1])-p[1]});
        for(int i=2;i<=n;i++) {
            _dp[i]=sqr(a[i])-(p[i]-p[i-1])+query(1, 1, N, a[i]);
            add(1, 1, N, {-2*a[i], _dp[i]+sqr(a[i])});
            //printf("%d %lld %lld _ %lld\n", i, _dp[i], query(1, N, a[i]), _dp[i]+p[i]);
        }
        printf("%lld", _dp[n]+p[n]);
    }

    return 0;
}
/* stuff you should look for
    - int overflow, array bounds
    - special/edge cases (n=1?)
    - do smth instead of nothing and stay organized
    - WRITE STUFF DOWN
    - DONT JUST STICK ON ONE APPROACH
*/

Compilation message (stderr)

building.cpp: In function 'int main()':
building.cpp:70:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
building.cpp:71:32: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |     for(int i=1;i<=n;i++) scanf("%d", &a[i]);
      |                           ~~~~~^~~~~~~~~~~~~
building.cpp:73:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         scanf("%d", &m);
      |         ~~~~~^~~~~~~~~~

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