Submission #574932

#	Time	Username	Problem	Language	Result	Execution time	Memory
574932		RealSnake	A Difficult(y) Choice (BOI21_books)	C++14	0 / 100	11 ms	336 KiB

books

#include "bits/stdc++.h"
using namespace std;
#include "books.h"

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

#define ll long long
#define mod 1000000007

int n, ind;
ll a;
ll pre[100001], arr[100001];
bool dp[100001][11][2];
bool yes;

void sol(int j, int k, ll sum, bool b) {
    if(dp[j][k][b])
        return;
    dp[j][k][b] = 1;
    if(j == n) {
        if(!k && sum >= a && sum <= 2 * a) {
            yes = 1;
            if(b)
                arr[ind++] = j;
        }
        return;
    }
    if(n - j < k || sum + (pre[n] - pre[n - k]) < a || sum + (pre[j + k] - pre[j]) > 2 * a)
        return;
    if(b)
        arr[ind++] = j;
    sol(j + 1, k, sum, 0);
    if(yes)
        return;
    if(k)
        sol(j + 1, k - 1, sum + (pre[j + 1] - pre[j]), 1);
    if(yes)
        return;
    if(b)
        ind--;
}

void solve(int nn, int k, ll A, int S) {
    // s = n;
    n = nn, a = A;
    for(int i = 1; i <= n; i++) {
        pre[i] = skim(i);
        pre[i] += pre[i - 1];
    }
    sol(0, k, 0LL, 0);
    if(yes) {
        vector<int> ans;
        for(int i = 0; i < k; i++)
            ans.push_back(arr[i]);
        answer(ans);
        return;
    }
    impossible();
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 15
• Subtask 3: 0 / 10
• Subtask 4: 0 / 15
• Subtask 5: 0 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20