제출 #542505

#제출 시각아이디문제언어결과실행 시간메모리
542505tabr코끼리 (Dancing Elephants) (IOI11_elephants)C++17
50 / 100
3614 ms3344 KiB
#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif

const int MAX_N = 150015;
const int MAX_B = 500;
int B;
int n;
int l;
int upd_cnt;
int x[MAX_N];
int pos[MAX_N];
int jump_cnt[MAX_N];
int jump_pos[MAX_N];
int e[MAX_B][MAX_B];
int sz[MAX_B];
int order[MAX_N];
 
void init(int n_, int l_, int x_[]) {
    n = n_;
    l = l_;
    B = (int) sqrt(n * 0.8);
    for (int i = 0; i < n; i++) {
        x[i] = x_[i];
    }
    iota(order, order + n, 0);
}
 
void build_one(int id) {
    sort(e[id], e[id] + sz[id], [&](int i, int j) {
        return x[i] < x[j];
    });
    for (int i = 0; i < sz[id]; i++) {
        pos[e[id][i]] = id;
    }
    for (int i = sz[id] - 1, j = sz[id]; i >= 0; i--) {
        while (j > 0 && x[e[id][j - 1]] > x[e[id][i]] + l) {
            j--;
        }
        if (j == sz[id]) {
            jump_cnt[e[id][i]] = 1;
            jump_pos[e[id][i]] = x[e[id][i]] + l + 1;
        } else {
            jump_cnt[e[id][i]] = jump_cnt[e[id][j]] + 1;
            jump_pos[e[id][i]] = jump_pos[e[id][j]];
        }
    }
}
 
void build() {
    sort(order, order + n, [&](int i, int j) {
        return x[i] < x[j];
    });
    for (int i = 0; i < B; i++) {
        sz[i] = 0;
        for (int j = n * i / B; j < n * (i + 1) / B; j++) {
            e[i][sz[i]] = order[j];
            sz[i]++;
        }
        build_one(i);
    }
}
 
int update(int i, int y) {
    if (n == 1) {
        return 1;
    }
    if (upd_cnt == 0) {
        build();
    }
    upd_cnt++;
    if (upd_cnt == n / B - 1) {
        upd_cnt = 0;
    }
    // remove x[i]
    for (int j = 0; j < sz[pos[i]] - 1; j++) {
        if (e[pos[i]][j] == i) {
            e[pos[i]][j] = e[pos[i]][sz[pos[i]] - 1];
            break;
        }
    }
    sz[pos[i]]--;
    build_one(pos[i]);
    // add x[i]
    x[i] = y;
    for (int id = 0; id < B; id++) {
        if (id == B - 1 || x[e[id + 1][0]] > y) {
            e[id][sz[id]] = i;
            sz[id]++;
            build_one(id);
            break;
        }
    }
    // answer
    int ans = 0;
    int now = 0;
    for (int id = 0; id < B; id++) {
        x[150001] = now;
        auto iter = lower_bound(e[id], e[id] + sz[id], 150001, [&](int j, int k) {
            return x[j] < x[k];
        });
        if (iter == e[id] + sz[id]) {
            continue;
        }
        ans += jump_cnt[*iter];
        now = jump_pos[*iter];
    }
    return ans;
}

mt19937 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count());

int rand_int(int a, int b) {  // [a, b]
    return uniform_int_distribution<int>(a, b)(rng);
}

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