제출 #971839

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
971839		GrindMachine	코끼리 (Dancing Elephants) (IOI11_elephants)	C++17	100 / 100	3438 ms	26508 KiB

elephants

#pragma GCC optimize("O3,unroll-loops")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
edi

*/

const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
const int B = 455;

#include "elephants.h"

int n,L;
vector<int> a;
set<pii> st;
vector<pii> blocks[N/B+5];
vector<int> block_num, cams, mx_point;

void upd_block(int b){
    if(blocks[b].empty()) return;
    auto &curr = blocks[b];
    int siz = sz(curr);
    int ptr = siz-1;
    rev(i,siz-1,0){
        while(curr[ptr].ff-curr[i].ff > L){
            ptr--;
        }

        int j = curr[i].ss;

        if(ptr+1 == siz){
            cams[j] = 1;
            mx_point[j] = curr[i].ff+L;
        }
        else{
            int k = curr[ptr+1].ss;
            cams[j] = cams[k]+1;
            mx_point[j] = mx_point[k];
        }
    }
}

void build(){
    int ind = 0;
    rep(i,n/B+1){
        blocks[i].clear();
    }

    for(auto [x,i] : st){
        blocks[ind/B].pb({x,i});
        block_num[i] = ind/B;
        ind++;
    }

    rep(b,n/B+1){
        upd_block(b);
    }
}

void init(int n_, int L_, int X[])
{
    n = n_;
    L = L_;
    a = block_num = cams = mx_point = vector<int>(n);
    rep(i,n) a[i] = X[i];
    rep(i,n) st.insert({a[i],i});
    build();
}

int upds = 0;

int update(int i, int v)
{
    upds++;
    if(upds%B == 0){
        build();
    }

    int b = block_num[i];

    {
        auto &curr = blocks[b];
        pii px = {a[i],i};
        curr.erase(find(all(curr),px));
        upd_block(b);
    }

    st.erase({a[i],i});
    a[i] = v;
    st.insert({a[i],i});
    auto it = st.find({a[i],i});

    if(next(it) != st.end()){
        b = block_num[next(it)->ss];
    }
    else if(it != st.begin()){
        b = block_num[prev(it)->ss];
    }
    else{
        b = 0;
    }

    block_num[i] = b;

    {
        auto &curr = blocks[b];
        pii px = {a[i],i};
        curr.insert(upper_bound(all(curr),px),px);
        upd_block(b);
    }

    int mx_reach = -1;
    int ans = 0;

    rep(b,n/B+1){
        auto &curr = blocks[b];
        pii px = {mx_reach+1,-1};
        auto it = upper_bound(all(curr),px);
        if(it == curr.end()){
            conts;
        }

        int j = it->second;
        ans += cams[j];
        mx_reach = mx_point[j];
    }  

    return ans;
}

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