Submission #731600

#	Time	Username	Problem	Language	Result	Execution time	Memory
731600		jasen_penchev	Aliens (IOI16_aliens)	C++14	41 / 100	714 ms	512876 KiB

aliens

/// Divide and Conquer Optimization
#include <algorithm>
#include <iostream>
#include <utility>
#include <vector>
#define endl '\n'
using namespace std;

const int MAXN = 4000;

long long dp[MAXN + 5][MAXN + 5];
long long cost[MAXN + 5][MAXN + 5];

void calc(int k, int from, int to, int mn, int mx)
{
    int mid = (from + to) / 2;
    int opt = -1;
    dp[mid][k] = (long long)(1e18);
    for (int i = max(k - 1, mn); i <= min(mid - 1, mx); ++ i)
    {
        if (dp[mid][k] > dp[i][k - 1] + cost[i + 1][mid])
        {
            dp[mid][k] = dp[i][k - 1] + cost[i + 1][mid];
            opt = i;
        }
    }
    if (from == to) return;
    if (from <= mid - 1) calc(k, from, mid - 1, mn, opt);
    if (mid + 1 <= to) calc(k, mid + 1, to, opt, mx);
}

long long take_photos(int n, int m, int k, vector<int> row, vector<int> col)
{
    vector< pair<int, int> > temp;
    for (int i = 0; i < n; ++ i)
    {
        temp.push_back({max(row[i], col[i]), min(row[i], col[i])});
    }
    sort(temp.begin(), temp.end());

    vector< pair<int, int> > interv;
    interv.push_back({-1, -1});
    for (auto [r, l] : temp)
    {
        while (interv.size() and interv.back().first >= l) interv.pop_back();
        interv.push_back({l, r});
    }

    n = interv.size() - 1;
    for (int i = 1; i <= n; ++ i)
    {
        for (int j = i; j <= n; ++ j)
        {
            cost[i][j] = 1ll * (interv[j].second - interv[i].first + 1) * (interv[j].second - interv[i].first + 1);
            cost[i][j] -= 1ll * max(0, interv[i - 1].second - interv[i].first + 1) * max(0, interv[i - 1].second - interv[i].first + 1);
        }
    }

    for (int i = 1; i <= n; ++ i)
    {
        dp[i][1] = cost[1][i];
    }

    long long ret = dp[n][1];
    for (int i = 2; i <= min(n, k); ++ i)
    {
        calc(i, i, n, i - 1, n - 1);
        ret = min(ret, dp[n][i]);
    }

    return ret;
}

/**int main()
{
    ios :: sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);

    int n, m, k;
    cin >> n >> m >> k;

    vector<int> row, col;
    for (int i = 1; i <= n; ++ i)
    {
        int r, c;
        cin >> r >> c;
        row.push_back(r);
        col.push_back(c);
    }

    cout << take_photos(n, m, k, row, col) << endl;

    return 0;
}*/

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:43:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   43 |     for (auto [r, l] : temp)
      |               ^

• Subtask 1: 4 / 4
• Subtask 2: 12 / 12
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40