Submission #825531

#	Time	Username	Problem	Language	Result	Execution time	Memory
825531		Boycl07	Building Bridges (CEOI17_building)	C++17	0 / 100	16 ms	3444 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 bad(pii x, pii y, pii z)
{
    return (double)(z.se - x.se) / (x.fi - z.fi)  > (double)(y.se - x.se) / (x.fi - y.fi) ;
}

int val(pii x, int y)
{
    return x.fi * y + x.se;
}

int top = 0;
pii st[N];

void add(pii line)
{
    int l = 1, r = top - 1, res = top;
    while(l <= r)
    {
        int mid = l + r >> 1;

        if(bad(st[mid - 1], st[mid], line))
            res = mid, r = mid  - 1;
        else l = mid + 1;
    }
    top = res + 1;
    st[res] = line;
}

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
        {
            int l = 0, r = top - 2, res = val(st[top - 1], h[i]);
            while(l <= r)
            {
                int mid = l + r >> 1;
                if(val(st[mid], h[i]) >= val(st[mid + 1], h[i]))
                    l = mid + 1;
                else r = mid - 1;
                minimize(res, val(st[mid], h[i]));
                minimize(res, val(st[mid + 1], h[i]));
            }
            dp[i] = res + sum[i - 1] + h[i] * h[i];

        }

        pii new_line = {-2 * h[i], h[i] * h[i] + dp[i] - sum[i]};
        add(new_line);
    }
    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 'void add(std::pair<long long int, long long int>)':
building.cpp:64:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   64 |         int mid = l + r >> 1;
      |                   ~~^~~
building.cpp: In function 'void solve()':
building.cpp:87:29: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   87 |                 int mid = l + r >> 1;
      |                           ~~^~~

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