Submission #741886

#	Time	Username	Problem	Language	Result	Execution time	Memory
741886		marvinthang	Fancy Fence (CEOI20_fancyfence)	C++17	100 / 100	63 ms	9804 KiB

fancyfence

/*************************************
*    author: marvinthang             *
*    created: 08.05.2023 10:24:39    *
*************************************/

#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 << '}'; }

const int MOD = 1e9 + 7;
namespace Mod {

    inline void fasterLLDivMod(unsigned long long x, unsigned y, unsigned &out_d, unsigned &out_m) {
        unsigned xh = (unsigned)(x >> 32), xl = (unsigned)x, d, m;
    #ifdef __GNUC__
        asm(
            "divl %4 \n\t"
            : "=a" (d), "=d" (m)
            : "d" (xh), "a" (xl), "r" (y)
        );
    #else
        __asm {
            mov edx, dword ptr[xh];
            mov eax, dword ptr[xl];
            div dword ptr[y];
            mov dword ptr[d], eax;
            mov dword ptr[m], edx;
        };
    #endif
        out_d = d; out_m = m;
    }

    template <class T> T invGeneral(T a, T b) {
        a %= b;
        if (!a) return b == 1 ? 0 : -1;
        T x = invGeneral(b, a);
        return x == -1 ? -1 : ((1 - 1LL * b * x) / a + b) % b;
    }

    template <int MOD>
    struct ModInt {
        
        unsigned int val;

        ModInt(void): val(0) {}
        ModInt(const long long &x) { *this = x; }

        ModInt & normalize(const unsigned int &v) {
            val = v >= MOD ? v - MOD : v;
            return *this;
        }

        bool operator ! (void) { return !val; }

        ModInt & operator = (const ModInt &x) { val = x.val; return *this; }
        ModInt & operator = (const long long &x) { return normalize(x % MOD + MOD); }

        ModInt operator - (void) { return ModInt(MOD - val); }

        ModInt & operator += (const ModInt &other) { return normalize(val + other.val); }
        ModInt & operator -= (const ModInt &other) { return normalize(val + MOD - other.val); }
        ModInt & operator /= (const ModInt &other) { return *this *= other.inv(); }

        ModInt & operator *= (const ModInt &other) {
            unsigned dummy;
            fasterLLDivMod((unsigned long long) val * other.val, MOD, dummy, val);
            return *this;
        }

        ModInt operator + (const ModInt &other) const { return ModInt(*this) += other; }
        ModInt operator - (const ModInt &other) const { return ModInt(*this) -= other; }
        ModInt operator * (const ModInt &other) const { return ModInt(*this) *= other; }
        ModInt operator / (const ModInt &other) const { return ModInt(*this) /= other; }

        ModInt pow(long long n) const {
            assert(n >= 0);
            ModInt res = 1, a = *this;
            for (; n; n >>= 1, a *= a) if (n & 1) res *= a;
            return res;
        }

        ModInt inv(void) const {
            int i = invGeneral((int) val, MOD);
            assert(~i);
            return i;
        }

        ModInt & operator ++ (void) { return *this += 1; }
        ModInt & operator -- (void) { return *this -= 1; }
        ModInt operator ++ (int) { ModInt old = *this; operator ++(); return old; }
        ModInt operator -- (int) { ModInt old = *this; operator --(); return old; }

        friend ModInt operator + (const long long &x, const ModInt &y) { return ModInt(x) + y; }
        friend ModInt operator - (const long long &x, const ModInt &y) { return ModInt(x) - y; }
        friend ModInt operator * (const long long &x, const ModInt &y) { return ModInt(x) * y; }
        friend ModInt operator / (const long long &x, const ModInt &y) { return ModInt(x) / y; }
        friend ostream & operator << (ostream &out, const ModInt &x) { return out << x.val; }
        friend istream & operator >> (istream &in, ModInt &x) { long long a; in >> a; x = a; return in; }

        bool operator < (const ModInt &other) const { return val < other.val; }
        bool operator > (const ModInt &other) const { return val > other.val; }
        bool operator <= (const ModInt &other) const { return val <= other.val; }
        bool operator >= (const ModInt &other) const { return val >= other.val; }
        bool operator == (const ModInt &other) const { return val == other.val; }
        bool operator != (const ModInt &other) const { return val != other.val; }
        explicit operator bool(void) const { return val; }
        explicit operator int(void) const { return val; }

    };  

    using Modular = ModInt <MOD>;

}

using namespace Mod;

// end of template

const int MAX = 1e5 + 5;

int N, H[MAX], W[MAX];

void init(void) {
	cin >> N;
	REP(i, N) cin >> H[i];
	REP(i, N) cin >> W[i];
}

vector <int> add[MAX];
int lab[MAX];
bool active[MAX];
Modular sum_w[MAX];
Modular sum_pair;

int find(int u) {
	return lab[u] < 0 ? u : lab[u] = find(lab[u]);
}

bool join(int u, int v) {
	u = find(u); v = find(v);
	if (u == v) return false;
	if (lab[u] > lab[v]) swap(u, v);
	sum_pair -= sum_w[u] * (sum_w[u] + 1) / 2;
	sum_pair -= sum_w[v] * (sum_w[v] + 1) / 2;
	sum_w[u] += sum_w[v];
	sum_pair += sum_w[u] * (sum_w[u] + 1) / 2;
	lab[u] += lab[v];
	lab[v] = u;
	return true;
}

void process(void) {
	vector <int> height {0};
	REP(i, N) {
		height.push_back(H[i]);
		sum_w[i] = W[i];
		lab[i] = -1;
	}
	sort(ALL(height));
	height.erase(unique(ALL(height)), height.end());
	REP(i, N) add[lower_bound(ALL(height), H[i]) - height.begin()].push_back(i);
	Modular res = 0;
	FORD(i, height.size(), 1) {
		for (int u: add[i]) {
			sum_pair += sum_w[u] * (sum_w[u] + 1) / 2;
			if (u && active[u - 1]) join(u, u - 1);
			if (u + 1 < N && active[u + 1]) join(u, u + 1);
			active[u] = true;
		}
		int l = height[i - 1] + 1;
		int r = height[i];
		res += 1LL * (r + l) * (r - l + 1) / 2 * sum_pair;
	}
	cout << res << '\n';
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
	file("A");
	init();
	process();
	cerr << "Time elapsed: " << TIME << " s.\n";
	return (0^0);
}

Compilation message (stderr)

fancyfence.cpp: In function 'int main()':
fancyfence.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
fancyfence.cpp:212:2: note: in expansion of macro 'file'
  212 |  file("A");
      |  ^~~~
fancyfence.cpp:30:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
fancyfence.cpp:212:2: note: in expansion of macro 'file'
  212 |  file("A");
      |  ^~~~

• Subtask 1: 0 / 0
• Subtask 2: 12 / 12
• Subtask 3: 13 / 13
• Subtask 4: 15 / 15
• Subtask 5: 15 / 15
• Subtask 6: 18 / 18
• Subtask 7: 27 / 27