Submission #1277422

#	Time	Username	Problem	Language	Result	Execution time	Memory
1277422		_filya_	Editor (BOI15_edi)	C++20	100 / 100	361 ms	27012 KiB

edi

#include <cassert>
#include <iostream>

const int MAX_N = 3e5 + 1;
const int MAX_D = 19;  // ceil(log2(3*(10^5)))

int state[MAX_N], par[MAX_N][MAX_D], lev[MAX_N];

/** get last op on active path of x with lev <= max_lev */
int get_par(int x, int max_lev) {
	if (lev[x] <= max_lev) { return x; }
	for (int i = MAX_D - 1; i >= 0; i--) {
		if (lev[par[x][i]] > max_lev) { x = par[x][i]; }
	}
	return par[x][0];
}

int main() {
	int n;
	std::cin >> n;
	for (int i = 1; i <= n; i++) {
		std::cin >> state[i];
		if (state[i] < 0) {
			lev[i] = -state[i];
			int z = get_par(i - 1, lev[i] - 1);
			assert(z);  // must be something to undo
			par[i][0] = get_par(z - 1, lev[i] - 1);

			// levels of ops in active path are strictly decreasing
			assert(lev[i] > lev[par[i][0]]);

			for (int j = 1; j < MAX_D; j++) {
				par[i][j] = par[par[i][j - 1]][j - 1];  // prepare binary jumps
			}
		}
		std::cout << state[get_par(i, 0)] << '\n';
		// current active path is i, par[i], par[par[i]], ...
	}
}

• Subtask 1: 20 / 20
• Subtask 2: 15 / 15
• Subtask 3: 28 / 28
• Subtask 4: 37 / 37