Submission #804932

#	Time	Username	Problem	Language	Result	Execution time	Memory
804932		becaido	Counting Mushrooms (IOI20_mushrooms)	C++17	91.87 / 100	7 ms	372 KiB

mushrooms

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifndef WAIMAI
#include "mushrooms.h"
#endif

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof...(u) ? ", " : ""), dout(u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

#ifdef WAIMAI
int use_machine(vector<int> x);
#endif

const int K = 125;

int count_mushrooms(int n) {
    int ans = 0, mx = min(n - 1, K);
    vector<int> id[2];
    id[0].pb(0);
    FOR (i, 1, mx) {
        vector<int> v;
        v.pb(0), v.pb(i);
        int cnt = use_machine(v);
        id[cnt].pb(i);
        if (max(id[0].size(), id[1].size()) == 2) break;
    }
    if (id[0].size() == 2) {
        int l = id[0].size() + id[1].size(), r = min(mx, l + 1);
        while (l <= mx) {
            vector<int> v;
            if (l == r) {
                v.pb(0), v.pb(l);
                int cnt = use_machine(v);
                id[cnt].pb(l);
            } else {
                v.pb(id[0][0]), v.pb(l), v.pb(id[0][1]), v.pb(r);
                int cnt = use_machine(v);
                id[cnt & 1].pb(r);
                id[cnt >> 1 & 1].pb(l);
            }
            l = r + 1;
            r = min(mx, l + 1);
        }
    } else if (id[1].size() == 2) {
        int l = id[0].size() + id[1].size(), r = min(mx, l + 1);
        while (l <= mx) {
            vector<int> v;
            if (l == r) {
                v.pb(0), v.pb(l);
                int cnt = use_machine(v);
                id[cnt].pb(l);
            } else {
                v.pb(id[1][0]), v.pb(l), v.pb(id[1][1]), v.pb(r);
                int cnt = use_machine(v);
                id[!(cnt & 1)].pb(r);
                id[!(cnt >> 1 & 1)].pb(l);
            }
            l = r + 1;
            r = min(mx, l + 1);
        }
    }
    ans += id[0].size();

    int l = mx + 1, r;
    while (l < n) {
        if (id[0].size() >= id[1].size()) {
            r = min<int>(n - 1, l + id[0].size() - 1);
            vector<int> v;
            for (int j = l; j <= r; j++) {
                v.pb(id[0][j - l]);
                v.pb(j);
            }
            int cnt = use_machine(v);
            ans += (r - l + 1) - (cnt + 1) / 2;
            id[cnt & 1].pb(r);
        } else {
            r = min<int>(n - 1, l + id[1].size() - 1);
            vector<int> v;
            for (int j = l; j <= r; j++) {
                v.pb(id[1][j - l]);
                v.pb(j);
            }
            int cnt = use_machine(v);
            ans += (cnt + 1) / 2;
            id[!(cnt & 1)].pb(r);
        }
        l = r + 1;
    }
    return ans;
}

/*
in1
3
0 1 1
out1
1
2

in2
4
0 1 0 0
out2
3
2
*/

#ifdef WAIMAI
static char fmt_buffer[100000];
#define FMT_TO_STR(fmt, result) va_list vargs; va_start(vargs, fmt); \
    vsnprintf(fmt_buffer, sizeof(fmt_buffer), fmt, vargs); \
    va_end(vargs); fmt_buffer[sizeof(fmt_buffer)-1] = 0; \
    string result(fmt_buffer);

static const int min_n = 2;
static const int max_n = 20000;
static const int max_qc = 20000;
static const int max_qs = 100000;
static const int species_A = 0;
static const int species_B = 1;

static int n;
static vector<int> species;
static int qc, qs;

static inline void error_if(bool cond, string message) {
    if (cond) {
        printf("%s\n", message.c_str());
        exit(0);
    }
}

static inline void wrong_if(bool cond, string message) {
    error_if(cond, "Wrong Answer: "+message);
}

int use_machine(vector<int> x) {
    const int xs = x.size();
    wrong_if(xs < 2, "Too small array for query.");
    wrong_if(xs > n, "Too large array for query.");
    qc++;
    wrong_if(qc > max_qc, "Too many queries.");
    qs += xs;
    wrong_if(qs > max_qs, "Too many total array sizes as queries.");
    for (int i = 0; i < xs; i++)
        wrong_if(x[i] < 0 || n - 1 < x[i], "Invalid value in the query array.");
    vector<bool> used(n, false);
    for (int i = 0; i < xs; i++) {
        wrong_if(used[x[i]], "Duplicate value in the query array.");
        used[x[i]] = true;
    }
    int diffs = 0;
    for (int i = 1; i < xs; i++)
        diffs += int(species[x[i]] != species[x[i-1]]);
    return diffs;
}

#ifdef __GNUC__
__attribute__ ((format(printf, 2, 3)))
#endif
static inline void check_input(bool cond, const char* message_fmt, ...) {
    FMT_TO_STR(message_fmt, message);
    error_if(!cond, "Invalid input: "+message);
}

int main() {
    check_input(1 == scanf("%d", &n), "Could not read n.");
    check_input(min_n <= n, "n must not be less than %d, but it is %d.", min_n, n);
    check_input(n <= max_n, "n must not be greater than %d, but it is %d.", max_n, n);
    species.resize(n);
    for (int i = 0; i < n; i++) {
        check_input(1 == scanf("%d", &species[i]), "Could not read species element [%d].", i);
        check_input(species[i]==species_A || species[i] == species_B,
                    "Species elements must be %d or %d, but species element [%d] is %d.", species_A, species_B, i, species[i]);
    }
    check_input(species[0] == species_A, "Species element [%d] must be %d.", 0, species_A);
    // Postponed closing standard input in order to allow interactive usage of the grader.

    qc = 0;
    qs = 0;
    int answer = count_mushrooms(n);
    printf("%d\n%d\n", answer, qc);
    fclose(stdout);
    fclose(stdin);
    return 0;
}
#endif

• Subtask 1: 91.8699 / 100