Submission #1145422

#	Time	Username	Problem	Language	Result	Execution time	Memory
1145422		Pekiban	Aliens (IOI16_aliens)	C++20	0 / 100	1 ms	328 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;

const int M = 1e6 + 5;

deque<int> dq;
ld dp[M], C[M];
struct line {
    ld k, c;
    ld f(ld x) {
        return k * x + c;
    };
} T[M];
ld X(line &A, line &B) {
    return (ld)(A.c - B.c) / (B.k - A.k);
}
long long take_photos(int n, int m, int k, vector<int> r, vector<int> c) {
    int mn[m+1];
    fill(mn, mn+m+1, 1e9);
    for (int i = 0; i < n; ++i) r[i]++, c[i]++;
    for (int i = 0; i < n; ++i) mn[max(r[i], c[i])] = min({mn[max(r[i], c[i])], r[i], c[i]});
    ld L = 0, R = m * (1ll) * m, ans = 1e18;
    for (int _ = 0; _ < 20; ++_) { // popravi!
        ld mid = (L + R)/2;
        T[0] = {0, 0}, dq = {0}, C[0] = 0;
        for (ll i = 1; i <= m; ++i) {
            if (mn[i] != 1e9) {
                int sz = dq.size(), p = -1;
                while (sz > 1 && dq[sz-1] >= mn[i]) p = dq[sz-1], dq.pop_back(), sz--; 
                while (dq.size() > 1 && X(T[dq[0]], T[dq[1]]) < i) dq.pop_front();
                dp[i] = T[dq[0]].f(i) + i * i + mid, C[i] = C[dq[0]]+1;
                if (p != -1) {
                    T[p] = {-2*p, dp[i] - i * i + 2 * i * p}; C[p] = C[i];
                    int sz = dq.size() - 1;
                    while (sz >= 1 && X(T[dq[sz-1]], T[p]) <= X(T[dq[sz-1]], T[dq[sz]])) dq.pop_back(), sz--;
                    dq.push_back(p);
                }
            }
            else
                dp[i] = dp[i-1], C[i] = C[i-1];
            int sz = dq.size()-1;
            T[i] = {-2*i, dp[i] - i * i + 2 * i * i};
            while (sz >= 1 && X(T[dq[sz-1]], T[i]) <= X(T[dq[sz-1]], T[dq[sz]])) dq.pop_back(), sz--;
            dq.push_back(i);
        }
        if (C[m] <= k)
            R = mid, ans = dp[m] - C[m] * mid;
        else
            L = mid;
    }
    return roundl(ans);
}

Compilation message (stderr)

aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:37:31: warning: narrowing conversion of '(-2 * p)' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
   37 |                     T[p] = {-2*p, dp[i] - i * i + 2 * i * p}; C[p] = C[i];
      |                             ~~^~
aliens.cpp:46:23: warning: narrowing conversion of '(-2 * i)' from 'll' {aka 'long long int'} to 'ld' {aka 'long double'} [-Wnarrowing]
   46 |             T[i] = {-2*i, dp[i] - i * i + 2 * i * i};
      |                     ~~^~
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: 0 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40