Submission #1139548

#	Time	Username	Problem	Language	Result	Execution time	Memory
1139548		gyg	Aliens (IOI16_aliens)	C++20	12 / 100	144 ms	4320 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define arr array
#define vec vector
#define pii pair<int, int>
#define fir first 
#define sec second 
const int N = 4e3 + 5, K = 4e3 + 5, INF = 1e18;

int n, k;
arr<int, N> ps, bck;

// Answer is min of dp[n][1], dp[n][2] ...
arr<arr<int, K>, N> dp;
int sq(int x) { return x * x; }
void dp_cmp() {
    for (int i = 1; i <= n; i++) {
        int mn = INF;
        for (int j = i; j >= 1; j--) mn = min(mn, bck[j]);
        dp[i][1] = sq(ps[i] - mn + 1);
    }

    for (int c = 2; c <= k; c++) {
        for (int i = 1; i <= n; i++) {
            dp[i][c] = INF;

            int ft = INF;
            for (int j = i + 1; j <= n; j++) ft = min(ft, bck[j]);

            int mn = bck[i];
            for (int j = i - 1; j >= 1; j--) {
                int intr = (ps[j] < mn) ? 0 :  sq(ps[j] - mn + 1);
                int trns = dp[j][c - 1] - intr + sq(ps[i] - mn + 1);
                if (mn <= ft)
                    dp[i][c] = min(dp[i][c], trns);
                mn = min(mn, bck[j]);
            }
        }
    }

    // for (int i = 1; i <= n; i++)
    //     for (int c = 1; c <= k; c++)
    //         cout << i << " " << c << ": " << dp[i][c] << endl;
}

map<int, int> bck_mp;
int take_photos(signed _sz, signed _m, signed _k, vec<signed> _rw, vec<signed> _cl) {
    k = _k;
    for (int i = 0; i < _sz; i++) {
        int x = max(_rw[i] + 1, _cl[i] + 1), y = min(_rw[i] + 1, _cl[i] + 1);
        if (!bck_mp.count(x)) bck_mp[x] = y; 
        else bck_mp[x] = min(bck_mp[x], y);
    }
    for (pii x : bck_mp) n++, ps[n] = x.fir, bck[n] = x.sec;
    
    dp_cmp();

    int ans = *min_element(dp[n].begin() + 1, dp[n].begin() + k + 1);
    return ans;
}

Compilation message (stderr)

aliens.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
aliens_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

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