Submission #524269

#	Time	Username	Problem	Language	Result	Execution time	Memory
524269		PurpleCrayon	Comparing Plants (IOI20_plants)	C++17	11 / 100	4096 ms	7940 KiB

plants

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

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

vector<int> par, chain;

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

    auto good_cand = [&](int i) -> bool {
        if (r[i]) return 0;
        if (done[i]) return 0;
        for (int x = i - k + 1; x < i; x++) if (!done[(x + n) % n] && !r[(x + n) % n])
            return 0;

        return 1;
    };

    for (int rep = 0; rep < n; rep++) {
        int me = -1;
        for (int i = 0; i < n; i++) if (good_cand(i)) me = i;
        assert(me != -1);

        // cerr << "me: " << me << '\n';

        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;
            // cerr << "set par[ " << (i + n) % n << "] = " << me << '\n';
        }
        for (int i = me + 1; i < me + k; i++) if (!done[i % n]) {
            chain[i % n] = me;
            // cerr << "set chain[ " << i % n << "] = " << me << '\n';
        }
    }
}

set<int> vis;
bool can_reach(int x, int y) {
    if (x == y) return true;
    vis.insert(x);
    for (int nxt : {par[x], chain[x]}) if (nxt != -1 && !vis.count(nxt)) {
        if (can_reach(nxt, y)) return 1;
    }
    return 0;
}

int compare_plants(int x, int y) {
    vis.clear();
    if (can_reach(x, y)) { // y is greater than x
        return -1;
    }
    vis.clear();
    if (can_reach(y, x)) { // x is greater than y
        return 1;
    }
    return 0;
}

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