Submission #1055570

#	Time	Username	Problem	Language	Result	Execution time	Memory
1055570		Trent	Packing Biscuits (IOI20_biscuits)	C++17	100 / 100	235 ms	1456 KiB

biscuits

#include "biscuits.h"
#include "bits/stdc++.h"
using namespace std;
#define forR(i, x) for(int i = 0; i < (x); ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
#define all(x) x.begin(), x.end()
typedef __int128_t ll;
typedef vector<ll> vll;

ll INF = 1e46 + 10;
ll mult(ll a, ll b) {
    return a > INF / b ? INF : a * b;
}
ll valOf(ll msk, vll& dc) {
    ll ret = 0;
    forR(i, dc.size()) if(msk & (1LL << i)) ret = min(INF, ret + dc[dc.size() - 1 - i]);
    return ret;
}
long long count_tastiness(long long x, std::vector<long long> a) {
    a.insert(a.begin(), (ll) 0);
    int k = 70;
    while(a.size() < k) a.push_back(0);
    vll ftp(k);
    vll sm(k);
    sm[0] = a[0];
    REP(i, 1, k) sm[i] = sm[i-1] + (((ll) 1) << (i-1)) * a[i];

    forR(i, k) {
        if(i == 0) ftp[i] = 1;
        else {
            ll st = sm[i];
            vll dc = {mult(((ll) 1) << (i-1), x)};
            ll msk = 0;
            for(int j = i-1; j >= 0; --j) {
                // st - dc(lo) >= sm[j], st - dc(hi) < sm[j]
                if(st - valOf(msk, dc) >= sm[j]) {
                    ll lo=msk, hi=(((ll) 1) << dc.size());
                    while(hi - lo > 1) {
                        ll mid = (lo+hi)/2;
                        if(st - valOf(mid, dc) >= sm[j]) lo = mid;
                        else hi = mid;
                    }
                    ftp[i] += (hi - msk) * ftp[j];
                    if(hi == (((ll) 1) << dc.size())) break;
                    msk = hi << 1;
                    dc.push_back((((ll) 1) << (j-1)) * x);
                } else {
                    msk <<= 1;
                    dc.push_back((((ll) 1) << (j-1)) * x);
                }
            }
        }
    }
    return ftp[k-1];
}

Compilation message (stderr)

biscuits.cpp:10:15: warning: overflow in conversion from 'double' to 'll' {aka '__int128'} changes value from '9.9999999999999999e+45' to '0x7fffffffffffffffffffffffffffffff' [-Woverflow]
   10 | ll INF = 1e46 + 10;
      |          ~~~~~^~~~
biscuits.cpp: In function 'll valOf(ll, vll&)':
biscuits.cpp:4:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<__int128>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    4 | #define forR(i, x) for(int i = 0; i < (x); ++i)
      |                                     ^
biscuits.cpp:16:5: note: in expansion of macro 'forR'
   16 |     forR(i, dc.size()) if(msk & (1LL << i)) ret = min(INF, ret + dc[dc.size() - 1 - i]);
      |     ^~~~
biscuits.cpp: In function 'long long int count_tastiness(long long int, std::vector<long long int>)':
biscuits.cpp:22:20: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   22 |     while(a.size() < k) a.push_back(0);
      |           ~~~~~~~~~^~~

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 21 / 21
• Subtask 4: 35 / 35
• Subtask 5: 23 / 23