Submission #304382

#	Time	Username	Problem	Language	Result	Execution time	Memory
304382		AlanC	Carnival Tickets (IOI20_tickets)	C++14	100 / 100	1236 ms	98416 KiB

tickets

#include "tickets.h"
#include <vector>
#include <algorithm>
#include <queue>
#define N 1505
using namespace std;

int n, m, k, cnt = 0, low[N], high[N], used[N];
vector<vector<int>> answer, a;
long long int total = 0;

struct Dat {
	long long int sum;
	int col, pos;
	
	Dat(){}
	
	Dat(long long int s, int c, int p) {
		sum = s;
		col = c;
		pos = p;
	}
	bool operator < (const Dat &d) {
		return sum < d.sum || (sum == d.sum && pos < d.pos);
	}
} D[N * N];


vector<pair<int, int>> small, large;

void prepDat() {
	for (int i=0; i<n; i++) {
		for (int j=0; j<k; j++) {
			D[cnt++] = Dat(a[i][j] + a[i][m-k+j], i, j);
		}
	}
}

void generateAnswer() {
	for (int i=0; i<n; i++) low[i] = 0;
	for (int i=0; i<cnt/2; i++)
		low[D[i].col] = max(low[D[i].col], D[i].pos + 1);

	int sum = 0;
	for (int i=0; i<n; i++) high[i] = k - low[i], sum += high[i];
	// if (sum != n * k / 2) while (true) {}
	
	small.clear(); large.clear();
	
	for (int i=0; i<n; i++) if (low[i] > 0) small.push_back(make_pair(low[i], i));
	for (int i=0; i<n; i++) if (high[i] > 0) large.push_back(make_pair(high[i], i));
	
	for (int i=0; i<n; i++) {
		vector<int> row(m, -1);
		answer.push_back(row);
		//printf("[%d] %d %d\n", i, low[i], high[i]);
	}

		sort(small.begin(), small.end(), greater<pair<int, int>>());
		sort(large.begin(), large.end(), greater<pair<int, int>>());
	
	for (int i=0; i<k; i++) {
		for (int j=0; j<n; j++) used[j] = 0;
		int x = 0, y = 0;
		
		for (int j=0; j<n/2; j++) {
			while (used[small[x].second]) x++;
			int c = small[x].second, p = small[x].first - 1;
			used[c] = 1;
			answer[c][p] = i;
			total -= a[c][p];
			low[c]--;
			x++;
		}
		
		for (int j=0; j<n/2; j++) {
			while (used[large[y].second]) y++;
			int c = large[y].second, p = m - large[y].first;
			used[c] = 1;
			answer[c][p] = i;
			total += a[c][p];
			high[c]--;
			y++;
		}
	
		
		small.clear();
		large.clear();
		
		for (int j=0; j<n; j++) if (low[j] > 0) small.push_back(make_pair(low[j], j));
		for (int j=0; j<n; j++) if (high[j] > 0) large.push_back(make_pair(high[j], j));
		
		sort(small.begin(), small.end(), greater<pair<int, int>>());
		sort(large.begin(), large.end(), greater<pair<int, int>>());
	}
	
	
}


long long find_maximum(int K, vector<vector<int>> x) {
	n = x.size();
	m = x[0].size();
	k = K;
	a = x;
	
	prepDat();
	
	sort(D, D + cnt);
	
	generateAnswer();
	
	allocate_tickets(answer);
	return total;
}

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