Submission #1048602

#	Time	Username	Problem	Language	Result	Execution time	Memory
1048602		becaido	Ancient Books (IOI17_books)	C++17	50 / 100	123 ms	41620 KiB

books

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

#ifdef WAIMAI
#include "grader.cpp"
#else
#include "books.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

const int SIZE = 1e6 + 5;

int n, L, R;
int p[SIZE];
int d[SIZE], in[SIZE], out[SIZE];
int add_in[SIZE], add_out[SIZE], add_d[SIZE];

ll minimum_walk(vector<int> p_, int s) {
    n = p_.size();
    s++;
    FOR (i, 1, n) {
        p[i] = p_[i - 1] + 1;
        in[i] = out[i] = 0;
        add_in[i] = add_out[i] = add_d[i] = 0;
    }

    FOR (i, 1, n) {
        if (i < p[i]) {
            out[i]++, out[p[i]]--;
            in[i + 1]++, in[p[i] + 1]--;
            d[i]++, d[p[i]]--;
        } else {
            out[p[i] + 1]++, out[i + 1]--;
            in[p[i]]++, in[i]--;
            d[p[i]]++, d[i]--;
        }
    }
    FOR (i, 1, n) {
        in[i] += in[i - 1];
        out[i] += out[i - 1];
        d[i] += d[i - 1];
    }

    L = 1, R = n;
    while (R > s && d[R - 1] == 0) R--;
    while (L < s && d[L] == 0) L++;
    if (L == R) return 0;
    vector<int> v[2];
    /* FOR (i, L, R) {
        int delta = out[i] - in[i];
        while (delta > 0) {
            if (v[1].size()) {
                int l = v[1].back();
                v[1].pop_back();
                add_out[l]++, add_out[i]--;
                add_in[l + 1]++, add_in[i + 1]--;
                add_d[l]++, add_d[i]--;
            } else {
                v[0].pb(i);
            }
            delta--;
        }
        while (delta < 0) {
            if (v[0].size()) {
                int l = v[0].back();
                v[0].pop_back();
                add_in[l]++, add_in[i]--;
                add_out[l + 1]++, add_out[i + 1]--;
                add_d[l]++, add_d[i]--;
            } else {
                v[1].pb(i);
            }
            delta++;
        }
    }

    assert(v[0].size() == 0 && v[1].size() == 0);
    FOR (i, L, R) {
        add_in[i] += add_in[i - 1], in[i] += add_in[i];
        add_out[i] += add_out[i - 1], out[i] += add_out[i];
        add_d[i] += add_d[i - 1], d[i] += add_d[i];
    } */
    ll ans = 0;
    FOR (i, L, R) {
        ans += out[i];
        if (i < R && d[i] == 0) ans += 2;
    }
    return ans;
}

/*
in1
4 0
0 2 3 1
out1
6
*/

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30