Submission #764529

#	Time	Username	Problem	Language	Result	Execution time	Memory
764529		marvinthang	Shortcut (IOI16_shortcut)	C++17	0 / 100	1 ms	212 KiB

shortcut

/*************************************
*    author: marvinthang             *
*    created: 23.06.2023 20:12:10    *
*************************************/

#include "shortcut.h"
#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// end of template

const int MAX = 1e6 + 6;
const long long INF = 1e9 * MAX;

long long find_shortcut(int n, vector <int> l, vector <int> d, int c) {
    vector <long long> x(n);
    REP(i, n - 1) x[i + 1] = x[i] + l[i];
    vector <long long> pos;
    REP(i, n) pos.push_back(x[i] - d[i]);
    sort(ALL(pos));
    pos.erase(unique(ALL(pos)), pos.end());
    int m = pos.size();
    vector <long long> max_d(m, -INF), min_d(m, INF), max_s(m, -INF), min_s(m, INF);
    REP(i, n) {
        int p = lower_bound(ALL(pos), x[i] - d[i]) - pos.begin();
        maximize(max_d[p], x[i] - d[i]);
        minimize(min_d[p], x[i] - d[i]);
        maximize(max_s[p], x[i] + d[i]);
        minimize(max_s[p], x[i] + d[i]);
    }
    auto check = [&] (long long f) {
        long long max_diff = INF, min_diff = -INF, max_sum = INF, min_sum = -INF;
        // REP(r, n) {
        //     int p = lower_bound(ALL(pos), x[r] + d[r] - f - c) - pos.begin() - 1;
        //     if (p >= 0) {
        //         minimize(max_diff, (x[r] - d[r]) - max_s[p] + f);
        //         maximize(min_diff, (x[r] + d[r]) - min_d[p] - f);
        //         minimize(max_sum, (x[r] - d[r]) + min_d[p] + f);
        //         maximize(min_sum, (x[r] + d[r]) + max_s[p] - f);
        //     }
        // }
        REP(r, n) REP(l, n) if ((x[r] + d[r]) - f - c > (x[l] - d[l])) {
            minimize(max_diff, (x[r] - d[r]) - (x[l] + d[l]) + f);
            maximize(min_diff, (x[r] + d[r]) - (x[l] - d[l]) - f);
            minimize(max_sum, (x[r] - d[r]) + (x[l] - d[l]) + f);
            maximize(min_sum, (x[r] + d[r]) + (x[l] + d[l]) - f);
        }
        auto check = [&] (int i, int j) {
            return min_diff <= x[i] - x[j] && x[i] - x[j] <= max_diff && min_sum <= x[i] + x[j] && x[i] + x[j] <= max_sum;
        };
        int j = 0, k = n - 1;
        REP(i, n) {
            while (j + 1 < n && x[j] < x[i] - max_diff) ++j;
            if (check(i, j)) return true;
            while (k && x[k - 1] >= min_sum - x[i]) --k;
            if (check(i, j) || check(i, k)) return true;
        }
        return false;
    };
    long long ll = *max_element(ALL(d));
    long long rr = x[n - 1] + 2 * ll;
    while (ll <= rr) {
        long long m = ll + rr >> 1;
        if (check(m - c)) rr = m - 1;
        else ll = m + 1;
    }
    return ll;
}

#ifdef LOCAL
#include <cstdio>
#include <cassert>
#include "shortcut.h"

int main()
{
    file("shortcut");
    int n, c;
    assert(2 == scanf("%d%d", &n, &c));
    
    std::vector<int> l(n - 1);
    std::vector<int> d(n);
    for (int i = 0; i < n - 1; i++)
        assert(1 == scanf("%d", &l[i]));
    for (int i = 0; i < n; i++)
        assert(1 == scanf("%d", &d[i]));
        
    long long t = find_shortcut(n, l, d, c);
    
    
    printf("%lld\n", t);
    
    return 0;
}
#endif

Compilation message (stderr)

shortcut.cpp: In function 'long long int find_shortcut(int, std::vector<int>, std::vector<int>, int)':
shortcut.cpp:99:26: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   99 |         long long m = ll + rr >> 1;
      |                       ~~~^~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 14
• Subtask 3: 0 / 8
• Subtask 4: 0 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3