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Submission #328590

# Submission time Handle Problem Language Result Execution time Memory
328590 2020-11-17T08:28:25 Z AmineWeslati Rice Hub (IOI11_ricehub) C++14
100 / 100
 21 ms 3456 KB 
//Never stop trying
/*#pragma GCC target ("avx2")
#pragma GCC optimize ("Ofast")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")*/
#include "bits/stdc++.h"
#ifndef LOCAL
#include "ricehub.h"
#endif
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

typedef long long ll;
typedef string str;
typedef double db;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
typedef vector<str> vs;
typedef vector<ld> vd;
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)

const int MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const int MX = 2e5 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up

template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
//constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());

ll random(ll a, ll b){
    return a + rng() % (b - a + 1);
}

#ifndef LOCAL  
#define cerr if(false) cerr
#endif
#define dbg(x) cerr << #x << " : " << x << endl; 
#define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;

void IO() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}

ll N,X[MX],B,pref[MX];

bool check(int n){
	FOR(i,0,N){
		int l=i-n/2,r=i+n-1-n/2;
		if(l>=0 && r<N){
			ll x=(n/2)*X[i]-(n-1-n/2)*X[i];
			if(i) x-=pref[i-1]; if(l) x+=pref[l-1];
			x+=pref[r]; x-=pref[i];
			/*if(n==3){
				cout << l << ' ' << r << endl;
				cout << x << endl;
			}*/
			if(x<=B) return true;
		}
	}
	return false;
}

int besthub(int NN, int L, int XX[], ll BB){
	N=NN; 
	FOR(i,0,N) X[i]=XX[i],pref[i]=X[i];
	FOR(i,1,N) pref[i]+=pref[i-1];
	B=BB;

	int l=1, r=N;
	int ans;
	while(l<=r){
		int n=(l+r)/2;
		if(check(n)){
			ans=n;
			l=n+1;
		}
		else r=n-1;
	}
	return ans;
}

#ifdef LOCAL
int main() {
    boost; IO();

    int L;
    cin>>N>>L>>B;
    int xx[N];
    FOR(i,0,N) cin>>xx[i];
    cout << besthub(N,L,xx,B) << endl;
    
    return 0;
}
#endif

/*
	.the fields in the optimal solution form a contiguous interval
	.when we fix an interval, the best location is the median
*/

/* Careful!!!
    .Array bounds
    .Infinite loops
    .Uninitialized variables / empty containers
    .Multisets are shit

   Some insights:
    .Binary search
    .Graph representation
    .Write brute force code
    .Change your approach
*/

Compilation message

ricehub.cpp: In function 'bool check(int)':
ricehub.cpp:75:4: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   75 |    if(i) x-=pref[i-1]; if(l) x+=pref[l-1];
      |    ^~
ricehub.cpp:75:24: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   75 |    if(i) x-=pref[i-1]; if(l) x+=pref[l-1];
      |                        ^~
ricehub.cpp: In function 'int besthub(int, int, int*, ll)':
ricehub.cpp:103:9: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
  103 |  return ans;
      |         ^~~

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 384 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 376 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 380 KB Output is correct
15 Correct 1 ms 384 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 1 ms 364 KB Output is correct
24 Correct 1 ms 364 KB Output is correct
25 Correct 1 ms 364 KB Output is correct
26 Correct 1 ms 364 KB Output is correct
27 Correct 1 ms 364 KB Output is correct
28 Correct 1 ms 364 KB Output is correct

Subtask #3
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 384 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 492 KB Output is correct
22 Correct 1 ms 492 KB Output is correct
23 Correct 1 ms 492 KB Output is correct
24 Correct 1 ms 492 KB Output is correct
25 Correct 2 ms 492 KB Output is correct
26 Correct 1 ms 492 KB Output is correct
27 Correct 1 ms 492 KB Output is correct
28 Correct 2 ms 492 KB Output is correct

Subtask #4
32.0 / 32.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 876 KB Output is correct
2 Correct 4 ms 876 KB Output is correct
3 Correct 19 ms 3456 KB Output is correct
4 Correct 18 ms 3308 KB Output is correct
5 Correct 9 ms 1644 KB Output is correct
6 Correct 9 ms 1792 KB Output is correct
7 Correct 16 ms 3052 KB Output is correct
8 Correct 16 ms 3052 KB Output is correct
9 Correct 8 ms 1644 KB Output is correct
10 Correct 8 ms 1644 KB Output is correct
11 Correct 18 ms 3308 KB Output is correct
12 Correct 18 ms 3308 KB Output is correct
13 Correct 9 ms 1772 KB Output is correct
14 Correct 9 ms 1772 KB Output is correct
15 Correct 13 ms 2540 KB Output is correct
16 Correct 14 ms 2540 KB Output is correct
17 Correct 16 ms 3052 KB Output is correct
18 Correct 21 ms 3052 KB Output is correct
19 Correct 16 ms 3180 KB Output is correct
20 Correct 17 ms 3180 KB Output is correct