Submission #1267413

#	Time	Username	Problem	Language	Result	Execution time	Memory
1267413		trvhung	Watching (JOI13_watching)	C++20	100 / 100	105 ms	16192 KiB

watching

#include <bits/stdc++.h>
// #include <ext/rope>
// #include <ext/pb_ds/assoc_container.hpp>

// using namespace __gnu_pbds;
// using namespace __gnu_cxx;
using namespace std;

// #define   ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define            ll long long
#define           ull unsigned long long
#define            ld long double
#define            pb push_back
#define  bit(mask, i) ((mask >> i) & 1)
#define            el '\n'
#define             F first
#define             S second

template <class X, class Y> bool maximize(X &x, const Y &y) { return (x < y ? x = y, 1 : 0); }
template <class X, class Y> bool minimize(X &x, const Y &y) { return (x > y ? x = y, 1 : 0); }

const int INF = 1e9;
const ll LINF = 1e18;
const int MOD = 1e9 + 7;
const int MULTI = 0;
const ld eps = 1e-9;
const int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0}; // R D L U
const int ddx[4] = {-1, 1, 1, -1}, ddy[4] = {1, 1, -1, -1}; // UR DR DL UL
const char cx[4] = {'R', 'D', 'L', 'U'};
const ll base = 31;
const int nMOD = 2;
const ll mods[] = {(ll)1e9 + 10777, (ll)1e9 + 19777, (ll)1e9 + 3, (ll)1e9 + 3777};

const int N = 2e3 + 5;
int n, p, q, a[N], limS[N], limL[N], dp[N][N];

bool check(int w) {
	memset(dp, 0x3f, sizeof(dp));

	for (int i = 1; i <= n; ++i) {
		limS[i] = limL[i] = i;

		int l = 1, r = i - 1;
		while (l <= r) {
			int mid = (l + r) >> 1;
			if (a[i] - a[mid] + 1 <= w) {
				limS[i] = mid;
				r = mid - 1;
			} else l = mid + 1;
		}

		l = 1, r = i - 1;
		while (l <= r) {
			int mid = (l + r) >> 1;
			if (a[i] - a[mid] + 1 <= 2 * w) {
				limL[i] = mid;
				r = mid - 1;
			} else l = mid + 1;
		}
	}

	dp[0][0] = 0;
	for (int i = 1; i <= n; ++i)
		for (int j = 0; j <= min(p, i); ++j) {
			if (j > 0 && dp[limS[i] - 1][j - 1] < INF) minimize(dp[i][j], dp[limS[i] - 1][j - 1]);
			if (dp[limL[i] - 1][j] < INF) minimize(dp[i][j], dp[limL[i] - 1][j] + 1);
		}

	for (int j = 1; j <= p; ++j)
		if (dp[n][j] <= q) 
			return 1;

	return 0;
}

void solve() {
	cin >> n >> p >> q;
	for (int i = 1; i <= n; ++i)
		cin >> a[i];

	minimize(p, n);
	minimize(q, n);

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

	int L = 1, R = INF, res = -1;
	while (L <= R) {
		int mid = (L + R) >> 1;
		if (check(mid)) {
			res = mid;
			R = mid - 1;
		} else L = mid + 1;
	}

	cout << res;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    if (!MULTI) solve();
    else {
        int test; cin >> test;
        while (test--) solve();
    }
    
    return 0;
}

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50