Submission #524259

#	Time	Username	Problem	Language	Result	Execution time	Memory
524259		PurpleCrayon	Comparing Plants (IOI20_plants)	C++17	0 / 100	1 ms	296 KiB

plants

#include "plants.h"
#include <bits/stdc++.h>
using namespace std;

#define sz(v) int(v.size())

vector<int> par;

void init(int k, vector<int> r) {
    int n = sz(r);
    vector<bool> done(n);
    par.assign(n, -1);

    auto get_cand = [&]() -> int {
        // find a zero that isn't covered by another
        
        vector<int> cand; cand.reserve(n);
        for (int i = 0; i < n; i++) if (r[i] == 0 && !done[i]) {
            cand.push_back(i);
        }
        for (int i = 0; i < sz(cand); i++) {
            int x = cand[i];

            int prv = cand[sz(cand) - 1];
            int dist = n - prv + x;
            if (i) {
                prv = cand[i - 1];
                dist = x - prv;
            }
            if (dist >= k) {
                return x;
            }
        }
        assert(false);
    };

    for (int rep = 0; rep < n; rep++) {
        int me = get_cand();
        done[me] = 1;
        for (int i = me - k + 1; i < me; i++) if (!done[(i + n) % n]) {
            r[(i + n) % n]--;
            par[(i + n) % n] = me;
        }
    }
}
bool can_reach(int x, int y) {
    if (x == -1) return 0;
    if (x == y) return 1;
    return can_reach(par[x], y);
}

int compare_plants(int x, int y) {
    if (can_reach(x, y)) { // y is greater than x
        return -1;
    } else if (can_reach(y, x)) { // x is greater than y
        return 1;
    } else { // impossible to determine
        return 0;
    }
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 14
• Subtask 3: 0 / 13
• Subtask 4: 0 / 17
• Subtask 5: 0 / 11
• Subtask 6: 0 / 15
• Subtask 7: 0 / 25