Submission #1033425

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033425		42kangaroo	Prisoner Challenge (IOI22_prison)	C++17	90 / 100	6 ms	1116 KiB

prison

#include "prison.h"

#include <vector>

std::vector<std::vector<int>> devise_strategy(int N) {
	using namespace std;
	vector<vector<int>> strat(22, vector<int>(N + 1, 0));
	vector<int> p3(8);
	p3[0] = 1;
	p3[1] = 4;
	p3[2] = 8;
	for (int i = 3; i < 8; ++i) {
		p3[i] = p3[i - 1] * 3;
	}
	strat[0][0] = 1;
	for (int i = 1; i <= N; ++i) {
		strat[0][i] = (i / p3[7]) + 1;
	}
	for (int i = 0; i < 5; ++i) {
		strat[1 + 3 * i][0] = strat[2 + 3 * i][0] = strat[3 + 3 * i][0] = i % 2;
		for (int j = 1; j <= N; ++j) {
			if ((j / p3[7 - i]) % 3 == 0) {
				strat[2 + 3 * i][j] = strat[3 + 3 * i][j] = -1 - i % 2;
				strat[1 + 3 * i][j] = 4 + 3 * i + (j / p3[6 - i]) % 3;
			} else if ((j / p3[7 - i]) % 3 == 1) {
				strat[3 + 3 * i][j] = -1 - i % 2;
				strat[1 + 3 * i][j] = -2 + i % 2;
				strat[2 + 3 * i][j] = 4 + 3 * i + (j / p3[6 - i]) % 3;
			} else {
				strat[2 + 3 * i][j] = strat[1 + 3 * i][j] = -2 + i % 2;
				strat[3 + 3 * i][j] = 4 + 3 * i + (j / p3[6 - i]) % 3;
			}
		}
	}
	strat[16][0] = strat[17][0] = strat[18][0] = 1;
	for (int i = 1; i <= N; ++i) {
		if ((i / p3[2]) % 3 == 0) {
			strat[17][i] = strat[18][i] = -2;
			strat[16][i] = 19 + (i >> 2) % 2;
		} else if ((i / p3[2]) % 3 == 1) {
			strat[18][i] = -2;
			strat[16][i] = -1;
			strat[17][i] = 19 + (i >> 2) % 2;
		} else {
			strat[17][i] = strat[16][i] = -1;
			strat[18][i] = 19 + (i >> 2) % 2;
		}
	}
	strat[19][0] = strat[20][0] = 0;
	strat[21][0] = 1;
	for (int i = 1; i <= N; ++i) {
		if ((i >> 2) % 2 == 0) {
			strat[20][i] = -1;
			if (i % 4 == 0) {
				strat[19][i] = -1;
			} else if (i % 4 == 3) {
				strat[19][i] = -2;
			} else {
				strat[19][i] = 21;
			}
		} else {
			strat[19][i] = -2;
			if (i % 4 == 0) {
				strat[20][i] = -1;
			} else if (i % 4 == 3) {
				strat[20][i] = -2;
			} else {
				strat[20][i] = 21;
			}
		}
		if (i%4 < 2) {
			strat[21][i] = -2;
		} else {
			strat[21][i] = -1;
		}
	}
	return strat;
}

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 80 / 90