Submission #804557

#	Time	Username	Problem	Language	Result	Execution time	Memory
804557		Blagoj	Dancing Elephants (IOI11_elephants)	C++17	100 / 100	2500 ms	14776 KiB

elephants

#include <bits/stdc++.h>
#include "elephants.h"
 
using namespace std;
 
int n, L;
const int K = 400;
 
int block[K][2 * K], nxt[K][2 * K], val[K][2 * K], sz[K], b[(int) 2e5+5], a[(int) 2e5+5];
pair<int, int> go[K][2 * K];
 
void make(int k) {
    int r = 0;
    for (int i = 0; i < sz[k]; i++) {
        while (r < sz[k] && block[k][r] - block[k][i] <= L) r++;
        nxt[k][i] = r;
        val[k][i] = block[k][i] + L;
    }
    for (int i = sz[k] - 1; i >= 0; i--) {
        if (nxt[k][i] == sz[k]) go[k][i] = {1, val[k][i]};
        else go[k][i] = {1 + go[k][nxt[k][i]].first, go[k][nxt[k][i]].second};
    }
}
 
 
void build() {
    n = 0;
    for (int i = 0; i < K; i++)
        for (int j = 0; j < sz[i]; j++) b[n++] = block[i][j];
    for (int i = 0; i < n; i += K) {
        int r = min(n, i + K);
        sz[i / K] = r - i;
        for (int j = i; j < r; j++) block[i / K][j - i] = b[j];
        make(i / K);
    }
}
 
void init(int N, int _L, int X[]) {
    n = N, L = _L;
    for (int i = 0; i < n; i++) b[i] = a[i] = X[i];
    for (int i = 0; i < n; i += K) {
        int r = min(n, i + K);
        sz[i / K] = r - i;
        for (int j = i; j < r; j++) block[i / K][j - i] = b[j];
    }
    build();
}
 
void erase(int i, int x) {
    for (int j = 0; j < sz[i]; j++) {
        if (block[i][j] < x) continue;
        block[i][j] = block[i][j + 1];
    }
    sz[i]--;
    make(i);
}
 
void del(int x) {
    for (int i = 0; i < K; i++) {
        if (x <= block[i][sz[i] - 1]) {
            erase(i, x);
            break;
        }
    }
}
 
void add(int i, int x) {
    int dummy = x;
    for (int j = 0; j < sz[i]; j++) {
        if (block[i][j] < x) continue;
        swap(block[i][j], dummy);
    }
    block[i][sz[i]++] = dummy;
    make(i);
}
 
void Update(int x) {
    for (int i = 0; i < K; i++) {
        if (x <= block[i][sz[i] - 1]) {
            add(i, x);
            break;
        }
        if (i == (n - 1) / K) {
            add(i, x);
            break;
        }
    }
}
 
int q = 0;
 
int update(int x, int y) {
    del(a[x]);
    a[x] = y;
    Update(a[x]);
    q++;
    if (q == K) {
        build();
        q = 0;
    }
    int ans = 0, pos = block[0][0], i = 0, j = 0;
    int cnt = 0;
    while (sz[i]) {
        ans += go[i][j].first;
        pos = go[i][j].second;
        while (sz[i] && block[i][sz[i] - 1] <= pos) i++;
        if (!sz[i]) break;
        int l = 0, r = sz[i] - 1;
        while (l < r) {
            int m = (l + r) / 2;
            if (block[i][m] <= pos) l = m + 1;
            else r = m;
        }
        j = r;
    }
    return ans;
}

Compilation message (stderr)

elephants.cpp: In function 'int update(int, int)':
elephants.cpp:102:9: warning: unused variable 'cnt' [-Wunused-variable]
  102 |     int cnt = 0;
      |         ^~~

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