Submission #770300

#	Time	Username	Problem	Language	Result	Execution time	Memory
770300		horiiseun	Mountains (NOI20_mountains)	C++17	100 / 100	670 ms	122540 KiB

Mountains

#include <iostream>
#include <vector>
#include <tuple>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <map>
#include <cmath>
#include <random>
#include <string>
#include <cassert>
#include <climits>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
using namespace std;

#define ll long long
#define f first
#define s second

void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }

template<typename A> void __print(const A &x);
template<typename A, typename B> void __print(const pair<A, B> &p);
template<typename... A> void __print(const tuple<A...> &t);
template<typename T> void __print(stack<T> s);
template<typename T> void __print(queue<T> q);
template<typename T, typename... U> void __print(priority_queue<T, U...> q);

template<typename A> void __print(const A &x) {
    bool first = true;
    cerr << '{';
    for (const auto &i : x) {
        cerr << (first ? "" : ","), __print(i);
        first = false;
    }
    cerr << '}';
}

template<typename A, typename B> void __print(const pair<A, B> &p) {
    cerr << '(';
    __print(p.f);
    cerr << ',';
    __print(p.s);
    cerr << ')';
}

template<typename... A> void __print(const tuple<A...> &t) {
    bool first = true;
    cerr << '(';
    apply([&first] (const auto &...args) { ((cerr << (first ? "" : ","), __print(args), first = false), ...); }, t);
    cerr << ')';
}

template<typename T> void __print(stack<T> s) {
    vector<T> debugVector;
    while (!s.empty()) {
        T t = s.top();
        debugVector.push_back(t);
        s.pop();
    }
    reverse(debugVector.begin(), debugVector.end());
    __print(debugVector);
}

template<typename T> void __print(queue<T> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.front();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}

template<typename T, typename... U> void __print(priority_queue<T, U...> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.top();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}

void _print() { cerr << "]\n"; }

template <typename Head, typename... Tail> void _print(const Head &H, const Tail &...T) {
    __print(H);
    if (sizeof...(T)) cerr << ", ";
    _print(T...);
}

#ifdef DEBUG
	#define D(...) cerr << "Line: " << __LINE__ << " [" << #__VA_ARGS__ << "] = ["; _print(__VA_ARGS__)
#else
	#define D(...)
#endif

void merge(vector<ll> &res, vector<ll> &l, vector<ll> &r) {
	int idx1 = 0, idx2 = 0;
	while (idx1 < l.size() && idx2 < r.size()) {
		if (l[idx1] <= r[idx2]) {
			res.push_back(l[idx1]);
			idx1++;
		} else {
			res.push_back(r[idx2]);
			idx2++;	
		}
	}
	while (idx1 < l.size()) {
		res.push_back(l[idx1]);
		idx1++;
	}
	while (idx2 < r.size()) {
		res.push_back(r[idx2]);
		idx2++;
	}
}

struct Node {
	int l, r;
	vector<ll> curr;
	Node *lft, *rht;
	Node (int tl, int tr, vector<ll> &v): l(tl), r(tr) {
		if (l + 1 != r) {
			lft = new Node(l, (l + r) / 2, v);
			rht = new Node((l + r) / 2, r, v);
			merge(curr, lft->curr, rht->curr);
		} else {
			lft = rht = NULL;
			curr.push_back(v[l]);
		}
	}
};

int query(Node *x, int l, int r, ll val) {
	if (r <= x->l || x->r <= l) {
		return 0;
	}
	if (l <= x->l && x->r <= r) {
		vector<ll>::iterator it = lower_bound(x->curr.begin(), x->curr.end(), val);
		return it - x->curr.begin();
	}
	return query(x->lft, l, r, val) + query(x->rht, l, r, val);
}

int n;
vector<ll> h;
Node *root;
ll ans, x;

int main() {

	ios_base::sync_with_stdio(false);
	cin.tie(0);

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x;
		h.push_back(x);
	}
	
	root = new Node(0, n, h);
	for (int i = 1; i < n - 1; i++) {
		ans += (ll) query(root, 0, i, h[i]) * (ll) query(root, i + 1, n, h[i]);
	}
	
	cout << ans << "\n";

}

Compilation message (stderr)

Mountains.cpp: In function 'void merge(std::vector<long long int>&, std::vector<long long int>&, std::vector<long long int>&)':
Mountains.cpp:116:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  116 |  while (idx1 < l.size() && idx2 < r.size()) {
      |         ~~~~~^~~~~~~~~~
Mountains.cpp:116:33: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  116 |  while (idx1 < l.size() && idx2 < r.size()) {
      |                            ~~~~~^~~~~~~~~~
Mountains.cpp:125:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  125 |  while (idx1 < l.size()) {
      |         ~~~~~^~~~~~~~~~
Mountains.cpp:129:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  129 |  while (idx2 < r.size()) {
      |         ~~~~~^~~~~~~~~~

• Subtask 1: 2 / 2
• Subtask 2: 4 / 4
• Subtask 3: 9 / 9
• Subtask 4: 36 / 36
• Subtask 5: 28 / 28
• Subtask 6: 9 / 9
• Subtask 7: 12 / 12