Submission #1095812

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095812		TVSown	Building Bridges (CEOI17_building)	C++17	100 / 100	43 ms	9852 KiB

building

///*** Sown_Vipro ***///
/// ->GIAI BA QUOC GIA<- ///

#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("popcnt")
#define F first
#define S second
#define pb push_back
#define ll long long
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define inp(name) if(fopen(name, "r")) freopen(name, "r", stdin);
#define out(name) if(fopen(name, "w")) freopen(name, "w", stdout);
#define szz(s) int(s.size())
#define int long long
const int N = 1e6 + 5, MAX = 1e6, oo = 1e9 + 5, MOD = 1e9 + 7;
int n;
int h[N], w[N];
long long s[N], dp[N];
struct Line {
    mutable ll k, m, p;
    bool operator<(const Line& o) const { return k < o.k; }
    bool operator<(ll x) const { return p < x; }
};

struct LineContainer : multiset<Line, less<>> {
    // (for doubles, use inf = 1/.0, div(a,b) = a/b)
    static const ll inf = LLONG_MAX;
    ll div(ll a, ll b) { // floored division
        return a / b - ((a ^ b) < 0 && a % b); }
    bool isect(iterator x, iterator y) {
        if (y == end()) return x->p = inf, 0;
        if (x->k == y->k) x->p = x->m > y->m ? inf : -inf;
        else x->p = div(y->m - x->m, x->k - y->k);
        return x->p >= y->p;
    }
    void add(ll k, ll m) {
        auto z = insert({k, m, 0}), y = z++, x = y;
        while (isect(y, z)) z = erase(z);
        if (x != begin() && isect(--x, y)) isect(x, y = erase(y));
        while ((y = x) != begin() && (--x)->p >= y->p)
            isect(x, erase(y));
    }
    ll query(ll x) {
        assert(!empty());
        auto l = *lower_bound(x);
        return l.k * x + l.m;
    }
} hull;

void solve(){
    cin >> n;
    for(int i = 1; i <= n; ++i){
        cin >> h[i];
    }
    for(int i = 1; i <= n; ++i){
        cin >> w[i];
        s[i] = s[i - 1] + w[i];
    }
    for(int i = 2; i <= n; ++i) dp[i] = 1e18;
    hull.add(2 * h[1], -(dp[1] + h[1] * h[1] - s[1]));
    for(int i = 2; i <= n; ++i){
        dp[i] = -hull.query(h[i]) + h[i] * h[i] + s[i - 1];
        hull.add(2 * h[i], -(dp[i] + h[i] * h[i] - s[i]));
    }
    cout << dp[n];
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    inp("in.txt");
    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

building.cpp: In function 'int main()':
building.cpp:15:47: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 | #define inp(name) if(fopen(name, "r")) freopen(name, "r", stdin);
      |                                        ~~~~~~~^~~~~~~~~~~~~~~~~~
building.cpp:75:5: note: in expansion of macro 'inp'
   75 |     inp("in.txt");
      |     ^~~

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