Submission #406116

#	Time	Username	Problem	Language	Result	Execution time	Memory
406116		tqbfjotld	A Difficult(y) Choice (BOI21_books)	C++14	100 / 100	3 ms	1024 KiB

books

#include "books.h"
#include <bits/stdc++.h>
#define int long long

using namespace std;
int cache[100005];
int n;
int query(int a){
    assert(a>=1 && a<=n);
    if (cache[a]!=-1) return cache[a];
    return cache[a] = skim(a);
}

int find_val(int a, int b, int c = 1, int d = n){
    if (query(c)>b) return -(c-1);
    if (query(c)>=a) return c;
    if (query(d)<a) return -d;
    if (query(d)<=b) return d;
    while (c+1<d){
        int mid = (c+d)/2;
        int t = query(mid);
        if (a<=t && t<=b) return mid;
        if (t<a) c = mid;
        else d = mid;
    }
    return -c;
}

void check_ans(vector<int32_t> t){
    int sum = 0;
    sort(t.begin(),t.end());
    for (int x = 1; x<t.size(); x++){
        assert(t[x-1]!=t[x]);
    }
}

void solve(int32_t N, int32_t K, long long A, int32_t S) {
    memset(cache,-1,sizeof(cache));
    n = N;

    int en = N;
    vector<int32_t> extr;
    for (int x = K-1; x>=0; x--){
        vector<int32_t> ans;
        for (int y = 0; y<x; y++){
            ans.push_back(y+1);
        }
        for (auto y : extr) ans.push_back(y);
        int sum = 0;
        for (auto x : ans){
            sum += query(x);
        }
        int res = find_val(A-sum,2*A-sum,x+1,en);
        if (res>0){
            ans.push_back(res);
            check_ans(ans);
            answer(ans);
            return;
        }
        en = -res-1;
        if (x>en){
            impossible();
            return;
        }
        extr.push_back(-res);
    }
    impossible();
}

Compilation message (stderr)

books.cpp: In function 'void check_ans(std::vector<int>)':
books.cpp:32:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |     for (int x = 1; x<t.size(); x++){
      |                     ~^~~~~~~~~
books.cpp:30:9: warning: unused variable 'sum' [-Wunused-variable]
   30 |     int sum = 0;
      |         ^~~

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