Submission #825547

#	Time	Username	Problem	Language	Result	Execution time	Memory
825547		Boycl07	Building Bridges (CEOI17_building)	C++17	0 / 100	2 ms	340 KiB

building

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define int ll
#define rep(i, n) for(int i = 1; i <= n; ++i)
#define forn(i, l, r) for(int i = l; i <= r; ++i)
#define ford(i, r, l) for(int i = r; i >= l; --i)
#define FOR(i, n) for(int i = 0; i < n; ++i)
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pli pair<ll, int>
#define pb push_back
#define task "test"
#define endl "\n"
#define sz(a) int(a.size())
#define bit(i, mask) (mask >> i & 1)
#define all(a) (a).begin(), (a).end()

template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }


const int N =  1e6 + 2;
const int S = N * 81 + 100;
const int M = 101;
const int K = 1e2 + 1;
const int MOD = 1e9 + 9;
const ll MOD2 = 1e9 + 9;
const int INF = 1e13 + 9999;
const ll LINF = 1e18 + 9999;
const int offset = N;
const int LIM = 1e6 + 2;
const int AL = 26;
const ll P = 1e15;
const int LOG = 16;

int n;

int dp[N], w[N], h[N], sum[N];

bool Q = 0;

struct line
{
    mutable int a, b, p;
    bool operator < (const line &x) const {
        return Q ? p < x.p : a < x.a;
    }
};

struct CHT : multiset<line> {

    int div(int x, int y)
    {
        return x / y - ((x ^ y) < 0 && x % y);
    }

    bool bad(iterator x, iterator y)
    {
        if(y == end()) {x -> p = INF; return 0;}
        if(x -> a == y -> a)
            x -> p = x -> b > y -> b ? INF : -INF;
        else
            x -> p = div(y -> b - x -> b, x -> a - y -> a);
        return x -> p >= y -> p;
    }

    void add(int a, int b)
    {
        auto z = insert({a, b, 0}), y = z++, x = y;
        while(bad(y, z)) z = erase(z);
        if(x != begin() && bad(--x, y)) bad(x, y = erase(y));
        while((y = x) != begin() && (--x) -> p >= y -> p)
            bad(x, erase(y));
    }

    int query(int x)
    {
        Q = 1;
        auto l = *lower_bound({0, 0, x}); Q = 0;
        return l.a * x + l.b;
    }
};

CHT st;

void solve()
{
    cin >> n;
    rep(i, n) cin >> h[i];
    rep(i, n) cin >> w[i], sum[i] = sum[i - 1] + w[i];
    rep(i, n)
    {

        if(i == 1) dp[i] = 0;
        else dp[i] = -st.query(h[i]) + h[i] * h[i] + sum[i - 1];
        st.add(2 * h[i], -(h[i] * h[i] + dp[i] - sum[i]));
    }
    cout << dp[n];
}


signed main()
{

    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    freopen("building.inp", "r", stdin);
    freopen("building.out", "w", stdout);

    int TC = 1;
    while(TC--)
    {
        solve();
        cout << endl;
        //reset
        //reset
        //reset
    }

    return 0;
}

Compilation message (stderr)

building.cpp: In function 'int main()':
building.cpp:114:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  114 |     freopen("building.inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
building.cpp:115:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  115 |     freopen("building.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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