제출 #1127122

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1127122		sosuke	Editor (BOI15_edi)	C++17	100 / 100	507 ms	27072 KiB

edi

#include <iostream>
#include <assert.h>

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 <= maxLev
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]; // prep 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