oj.uz

Submission #520839

# Submission time Handle Problem Language Result Execution time Memory
520839 2022-01-31T06:52:27 Z SmolBrain Watching (JOI13_watching) C++17
0 / 100
 1000 ms 262148 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long int ll;
typedef long double ld;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define pb push_back
#define conts continue
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define trav(i,a) for(auto &i : a)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;

ll dp[2005][maxn];

void solve(int test_case)
{
    // referred to external solutions
    ll n, p, q; cin >> n >> p >> q;
    vector<ll> a(n + 5);
    rep1(i, n) cin >> a[i];

    sort(a.begin() + 1, a.begin() + n + 1);

    auto check = [&](ll k) {
        // dp[i][j] = min no.of large cameras required to cover all events from [1..i] using j small cameras
        // large[i] = right most position for which a[pos] < a[i] - (2 * k) + 1
        // small[i] = right most position for which a[pos] < a[i] - k + 1

        rep(i, n + 5) rep(j, p + 5) dp[i][j] = inf2;
        vector<ll> large(n + 5), small(n + 5);
        rep1(i, n) {
            auto it = lower_bound(a.begin() + 1, a.begin() + n + 1, a[i] - (2 * k) + 1);
            ll pos = max(ll(it - a.begin() - 1), 0ll);
            large[i] = pos;
        }

        rep1(i, n) {
            auto it = lower_bound(a.begin() + 1, a.begin() + n + 1, a[i] - k + 1);
            ll pos = max(ll(it - a.begin() - 1), 0ll);
            small[i] = pos;
        }

        dp[0][0] = 0;

        rep1(i, n) {
            rep(j, p + 1) {
                // place large cam
                ll pos1 = large[i];
                dp[i][j] = min(dp[i][j], dp[pos1][j] + 1);

                // place small cam
                if (j) {
                    ll pos2 = small[i];
                    dp[i][j] = min(dp[i][j], dp[pos2][j - 1]);
                }
            }
        }

        rep(j, p + 1) {
            if (dp[n][j] <= q) {
                return true;
            }
        }

        return false;
    };

    ll l = 1, r = inf1;
    ll ans = inf2;

    while (l <= r) {
        ll mid = (l + r) / 2;
        if (check(mid)) {
            ans = min(ans, mid);
            r = mid - 1;
        }
        else {
            l = mid + 1;
        }
    }

    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;
    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message

watching.cpp: In function 'void usaco(std::string)':
watching.cpp:56:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:57:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 844 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 992 ms 82504 KB Output is correct
5 Correct 1 ms 844 KB Output is correct
6 Execution timed out 1024 ms 82500 KB Time limit exceeded
7 Halted 0 ms 0 KB -

Subtask #2
0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 11468 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 334 ms 34984 KB Output is correct
4 Runtime error 111 ms 262148 KB Execution killed with signal 9
5 Halted 0 ms 0 KB -