Submission #764550

#	Time	Username	Problem	Language	Result	Execution time	Memory
764550		marvinthang	Shortcut (IOI16_shortcut)	C++17	100 / 100	1298 ms	86208 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;

void up_max(pair <long long, long long> &a, long long b) {
    if (a.fi < b) {
        a.se = a.fi;
        a.fi = b;
    } else maximize(a.se, b);
}
void up_min(pair <long long, long long> &a, long long b) {
    if (a.fi > b) {
        a.se = a.fi;
        a.fi = b;
    } else minimize(a.se, b);
}

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> v_d;
    REP(i, n) v_d.push_back(x[i] - d[i]);
    sort(ALL(v_d));
    v_d.erase(unique(ALL(v_d)), v_d.end());
    int m = v_d.size();
    vector <pair <long long, long long>> max_s(m, make_pair(-INF, -INF)), min_d(m, make_pair(INF, INF));
    REP(i, n) {
        int p = lower_bound(ALL(v_d), x[i] - d[i]) - v_d.begin();
        up_min(min_d[p], x[i] - d[i]);
        up_max(max_s[p], x[i] + d[i]);
    }
    REP(i, m - 1) {
        up_min(min_d[i + 1], min_d[i].fi);
        up_min(min_d[i + 1], min_d[i].se);
        up_max(max_s[i + 1], max_s[i].fi);
        up_max(max_s[i + 1], max_s[i].se);
    }

    vector <int> p_s(n);
    iota(ALL(p_s), 0);
    sort(ALL(p_s), [&] (int a, int b) { return x[a] + d[a] < x[b] + d[b]; });
    auto check = [&] (long long f) {
        long long max_diff = INF, min_diff = -INF, max_sum = INF, min_sum = -INF;
        int l = -1;
        for (int r: p_s) {
            while (l + 1 < m && v_d[l + 1] < x[r] + d[r] - f - c) ++l;
            if (l >= 0) {
                long long a = max_s[l].fi == x[r] + d[r] ? max_s[l].se : max_s[l].fi;
                long long b = min_d[l].fi == x[r] - d[r] ? min_d[l].se : min_d[l].fi;
                minimize(max_diff, (x[r] - d[r]) - a + f);
                maximize(min_diff, (x[r] + d[r]) - b - f);
                minimize(max_sum, (x[r] - d[r]) + b + f);
                maximize(min_sum, (x[r] + d[r]) + a - 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:118:26: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  118 |         long long m = ll + rr >> 1;
      |                       ~~~^~~~

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