Submission #1167360

#	Time	Username	Problem	Language	Result	Execution time	Memory
1167360		gyg	Carnival Tickets (IOI20_tickets)	C++20	27 / 100	355 ms	92752 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
using namespace std;
#define int long long 
#define sig signed 
#define arr array 
#define vec vector 
#define pii pair<int, int>
#define fir first 
#define sec second
#define mp make_pair
const int N = 1505, M = 1505, INF = 1e18;

int n, m, k;
arr<arr<int, M>, N> a;

arr<int, N> lst, mst;
void prp_cmp() {
	for (int i = 1; i <= n; i++) {
		lst[i] = *min_element(a[i].begin() + 1, a[i].begin() + m + 1);
		mst[i] = *max_element(a[i].begin() + 1, a[i].begin() + m + 1);

		// cout << i << ": " << lst[i] << " " << mst[i] << '\n';
	}
}

arr<arr<pii, N>, N> dp;
void dp_cmp() {
	dp[0].fill({-INF, -1});
	dp[0][0] = {0, -1};
	for (int i = 1; i <= n; i++) {
		for (int c = 0; c <= n / 2; c++) {
			int tk = (c == 0) ? -INF : dp[i - 1][c - 1].fir + mst[i];
			int lv = dp[i - 1][c].fir - lst[i];
			dp[i][c] = max(mp(tk, 1), mp(lv, 0));
		}
	}
}

arr<int, N> dr;
void dr_cmp() {
	int i = n, c = n / 2;
	while (i != 0) {
		dr[i] = dp[i][c].sec;
		if (dr[i] == 0) i--;
		else i--, c--;
	}

	// for (int i = 1; i <= n; i++) {
	// 	cout << i << ": " << dr[i] << '\n';
	// }
}

void ans_cmp() {
	vec<vec<sig>> ass;
	for (int i = 1; i <= n; i++) {
		int mn = min_element(a[i].begin() + 1, a[i].begin() + m + 1) - a[i].begin();
		int mx = max_element(a[i].begin() + 1, a[i].begin() + m + 1) - a[i].begin();

		vec<sig> x(m, -1);
		if (dr[i] == 0) x[mn - 1] = 0;
		else x[mx - 1] = 0;
		ass.push_back(x);
	}
	allocate_tickets(ass);
}

// Return indices 0-indexed
int find_maximum(sig _k, vec<vec<sig>> _a) {
	n = _a.size(), m = _a[0].size(), k = _k;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			a[i][j] = _a[i - 1][j - 1];
	
	prp_cmp();
	dp_cmp();
	dr_cmp();
	ans_cmp();

	return dp[n][n / 2].fir;
}

• Subtask 1: 11 / 11
• Subtask 2: 16 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10