Submission #562806

#	Time	Username	Problem	Language	Result	Execution time	Memory
562806		elazarkoren	Aliens (IOI16_aliens)	C++17	12 / 100	19 ms	356 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define chkmin(a, b) a = min(a, b)
#define chkmax(a, b) a = max(a, b)
//#define int ll
using namespace std;
//typedef __int128_t ll;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pii;
typedef vector<pii> vii;

const int MAX_N = 1e5 + 5;
const ll infinity = 1e18;

pii dp[MAX_N];
int ind[MAX_N];
int prefix_max[MAX_N];
int r[MAX_N], c[MAX_N];

bitset<MAX_N> inside;

int n, m;

pii Solve(ll lambda) {
    for (int i = 0; i < n; i++) {
        dp[i] = {infinity, infinity};
        int left = m, right = 0;
        for (int l = i; l >= 0; l--) {
            chkmin(left, int(r[ind[l]]));
            chkmax(right, int(c[ind[l]] + 1));
            ll x = (l ? dp[l - 1].x : 0) + ll(right - left) * (right - left) + lambda;
            if (prefix_max[l] > left) {
                x -= ll(prefix_max[l] - left) * (prefix_max[l] - left);
            }
            ll cnt = l ? dp[l - 1].y : 0;
            chkmin(dp[i], pii(x, cnt + 1));
        }
    }
    return dp[n - 1];
}

long long take_photos(int32_t N, int32_t M, int32_t k, std::vector<int32_t> R, std::vector<int32_t> C) {
    n = N, m = M;
    for (int i = 0; i < n; i++) {
        r[i] = R[i], c[i] = C[i];
        if (r[i] > c[i]) swap(r[i], c[i]);
    }
    iota(ind, ind + n, 0);
    sort(ind, ind + n, [&] (int i, int j) {
        return r[i] == r[j] ? c[i] < c[j] : r[i] < r[j];
    });
    int max_c = 0;
    for (int i = 0; i < n; i++) {
        if (max_c > c[ind[i]]) {
            inside[ind[i]] = true;
            r[ind[i]] = m + 1, c[ind[i]] = m + 1;
        }
        chkmax(max_c, c[ind[i]]);
    }
    sort(ind, ind + n, [&] (int i, int j) {
        return r[i] + c[i] < r[j] + c[j];
    });
    n -= inside.count();
    for (int i = 0; i < n; i++) {
        prefix_max[i + 1] = max(prefix_max[i], c[ind[i]] + 1);
    }
    pii p = Solve(0);
    if (p.y <= k) return p.x;
    ll begin = 0, end = ll(m) * m + 5, mid;
    while (begin < end) {
        mid = (begin + end) >> 1;
        p = Solve(mid);
        if (p.y <= k) end = mid;
        else begin = mid + 1;
    }
    return Solve(end).x - k * (end);
}
//6 7 2
//0 3
//4 4
//4 6
//4 5
//4 6
//0 5

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