Submission #814826

#	Time	Username	Problem	Language	Result	Execution time	Memory
814826		winter0101	A Difficult(y) Choice (BOI21_books)	C++14	100 / 100	1 ms	336 KiB

books

#include<bits/stdc++.h>
#include "books.h"
using namespace std;
#define all(fl) fl.begin(),fl.end()
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define lb lower_bound
#define ub upper_bound
#define sz(a) (int)a.size()
#define pii pair<int,int>
#define pli pair<long long,int>
#define gcd __gcd
#define lcm(x,y) x*y/__gcd(x,y)
/*typedef long long ll;

void __attribute__((noreturn)) __attribute__((format(printf, 1, 2))) result(const char *msg, ...)
{
    va_list args;
    va_start(args, msg);
    vfprintf(stderr, msg, args);
    fprintf(stderr, "\n");
    va_end(args);
    exit(0);
}

namespace
{
    int N, K, S, sUsed;
    long long A;
    vector<long long> seq;
}

void impossible()
{
    result("Impossible (not checked): %d book(s) skimmed", sUsed);
    exit(0);
}

long long skim(int pos)
{
    printf("skim(%d): ", pos);
	if (pos<1 || pos>N) result("Invalid skim");
    printf("%lld\n", seq[pos]);
	sUsed++;
	if (sUsed>S) result("Out of books to skim");
    return seq[pos];
}

void answer(vector<int> v)
{
    printf("answer({");
    for(int i = 0; i < (int) v.size(); ++i)
    {
        printf("%d", v[i]);
        if(i + 1 != (int) v.size()) printf(", ");
    }
    printf("})\n");

	if ((int) v.size() != K) result("Invalid answer");
   	ll sum = 0;
	for(auto x: v) {
		if (x<1 || x>N) result("Invalid answer");
		sum += seq[x];
	}
	if (sum < A || 2*A<sum) result("Wrong answer");

	result("Correct: %d book(s) skimmed", sUsed);
    exit(0);
}*/
const int maxn=1e5+9;
long long a[maxn];
long long b[maxn];
long long ask(int id){
if (a[id])return a[id];
return a[id]=skim(id);
}
void solve(int n,int k,long long A,int s){
for1(i,1,k-1){
a[i]=ask(i);
b[i]=b[i-1]+a[i];
}
vector<int>id;
long long sum=0;
for1(i,1,k){
int l=k-i+1,r=n,c1=-1;
if (!id.empty())r=id.back()-1;
long long v1=ask(r);
if (v1+sum+b[k-i]<=2*A){
    c1=r;
    id.pb(c1);
    sum+=a[c1];
    if (sum+b[k-i]>=A){
        for1(j,1,k-i){
        id.pb(j);
        }
        answer(id);
        return;
    }
    continue;
}
while (l<=r){
    int mid=(l+r)/2;
    long long vl=ask(mid);
    if (vl+sum+b[k-i]<=2*A){
        l=mid+1;
        c1=mid;
    }
    else r=mid-1;
}
//cerr<<c1<<'\n';
if (c1==-1)break;
id.pb(c1);
sum+=a[c1];
if (sum+b[k-i]>=A){
    for1(j,1,k-i){
    id.pb(j);
    }
    answer(id);
    return;
}
//cerr<<c1<<" "<<sum<<'\n';
}
if (sz(id)!=k||sum<A){
    impossible();   
}
else {
    answer(id);
}
}
/*signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    //freopen(".INP","r",stdin);
    //freopen(".OUT","w",stdout);
     if(scanf("%d %d %lld %d", &N, &K, &A, &S) != 4)
        result("Invalid input");

    seq.resize(N + 1);
    for(int i = 1; i <= N; ++i) {
    	if(scanf("%lld", &(seq[i])) != 1) result("Invalid input");
		if(i>1 && seq[i]<=seq[i-1]) result("Invalid input");
   	}

    solve(N, K, A, S);

    result("No answer");
}*/

• 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