Submission #752232

#	Time	Username	Problem	Language	Result	Execution time	Memory
752232		marvinthang	Dancing Elephants (IOI11_elephants)	C++17	100 / 100	6776 ms	11236 KiB

elephants

/*************************************
*    author: marvinthang             *
*    created: 02.06.2023 20:52:17    *
*************************************/

#include "elephants.h"
#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }

// end of template

const int MAX = 1.5e5 + 5;
const int BUCKET_SIZE = 1210;

int N, L, X[MAX], cnt, numBucket;
vector <int> buckets[MAX / BUCKET_SIZE + 23];
pair <int, int> nxt[MAX];

bool cmp(int x, int y) {
    return make_pair(X[x], x) < make_pair(X[y], y);
}

void build_bucket(int b) {
    int n = buckets[b].size();
    int j = n;
    REPD(x, n) {
        int i = buckets[b][x];
        while (X[buckets[b][j - 1]] > X[i] + L) --j;
        if (j == n) nxt[i] = make_pair(X[i] + L, 1);
        else nxt[i] = make_pair(nxt[buckets[b][j]].fi, nxt[buckets[b][j]].se + 1);
    }
}

void bucket_add(int b, int i) {
    buckets[b].insert(upper_bound(ALL(buckets[b]), i, cmp), i);
    build_bucket(b);
}

void bucket_erase(int b, int i) {
    buckets[b].erase(find(ALL(buckets[b]), i));
    build_bucket(b);
}

void build(void) {
    vector <int> pos(N);
    iota(ALL(pos), 0);
    sort(ALL(pos), cmp);
    REP(i, numBucket) buckets[i].clear();
    REP(i, N) buckets[i / BUCKET_SIZE].push_back(pos[i]);
    REP(i, numBucket) build_bucket(i);
}

void init(int n, int l, int x[]) {
    N = n; L = l;
    numBucket = (N - 1) / BUCKET_SIZE + 1;
    REP(i, N) X[i] = x[i];
    build();
}

int get_answer(void) {
    int res = 0;
    X[N] = -1;
    REP(b, numBucket) if (!buckets[b].empty()) {
        int p = upper_bound(ALL(buckets[b]), N, cmp) - buckets[b].begin();
        if (p == buckets[b].size()) continue;
        p = buckets[b][p];
        res += nxt[p].se;
        X[N] = nxt[p].fi;
    }
    return res;
}

int update(int i, int y) {
    REP(b, numBucket) if (!buckets[b].empty() && !cmp(buckets[b].back(), i)) {
        bucket_erase(b, i);
        break;
    }
    X[i] = y;
    REP(b, numBucket) if (b == numBucket - 1 || (!buckets[b].empty() && !cmp(buckets[b].back(), i))) {
        bucket_add(b, i);
        break;
    }
    if (++cnt == BUCKET_SIZE) {
        build();
        cnt = 0;
    }
    return get_answer();
}

#ifdef LOCAL
#include "elephants.h"
#include <stdio.h>
#include <stdlib.h>

#define MAX_N 1000000
#define MAX_M 1000000

static int n,l,m;
static int x[MAX_N];
static int ii[MAX_M];
static int yy[MAX_M];
static int sol[MAX_M];

inline 
void my_assert(int e) {if (!e) abort();}

void read_input()
{
  int i;
  my_assert(3==scanf("%d %d %d",&n,&l,&m));
  for(i=0; i<n; i++)
    my_assert(1==scanf("%d",&x[i]));
  for(i=0; i<m; i++)
    my_assert(3==scanf("%d %d %d",&ii[i],&yy[i],&sol[i]));
}

int main()
{
    file("elephants");
  int i, ans;

  read_input();
  init(n,l,x);
  for(i=0; i<m; i++) {
    ans = update(ii[i],yy[i]);
    if(ans==sol[i])continue;
      printf("Incorrect.  In %d-th move, answered %d (%d expected).\n",
       i+1, ans, sol[i]);
    return 0;
  }
  printf("Correct.\n");
  return 0;
}
#endif

Compilation message (stderr)

elephants.cpp: In function 'int get_answer()':
elephants.cpp:99:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   99 |         if (p == buckets[b].size()) continue;
      |             ~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 24 / 24
• Subtask 4: 47 / 47
• Subtask 5: 3 / 3