Submission #570153

#	Time	Username	Problem	Language	Result	Execution time	Memory
570153		Joshi503	Mountains (NOI20_mountains)	C++14	64 / 100	2092 ms	7032 KiB

Mountains

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using db = long double;
using str = string;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
#define f first
#define s second

#define tcT template<class T
#define tcTU tcT, class U
tcT> using V = vector<T>;
tcT, size_t SZ > using AR = array<T, SZ>;
using vi = V<int>;
using vb = V<bool>;
using vl = V<ll>;
using vd = V<db>;
using vs = V<str>;
using vpi = V<pi>;
using vpl = V<pl>;

#define sz(x) int((x).size())
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) x.rbegin(), x.rend() 
#define sor(x) sort(all(x)) 
#define pb push_back

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = ((b)-1); i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define rep(a) F0R(_,a)
#define each(a,x) for (auto& a: x)

const ll MOD = 1e9 + 7;
const ll MX = 1e9;
const ll INF = 1e18;
const db PI = acos((db)-1);
const int ddef[4]{ 1,0,-1,0 }, dataq[4]{ 0,1,0,-1 };
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
template<class T> using pqg = priority_queue<T, vector<T>, greater<T>>;

void setIO(string name = "") {
    ios_base::sync_with_stdio(0); cin.tie(0);
    if (sz(name)) {
        freopen((name + ".in").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}

void _print(char i) { cerr << i; }
void _print(string i) { cerr << i; }
void _print(float i) { cerr << i; }
void _print(int i) { cerr << i; }
void _print(double i) { cerr << i; }
void _print() { cerr << "\n"; };
template<typename x, typename y> void _print(pair<x, y>& t) { cerr << "{";_print(t.first);cerr << ", ";_print(t.second);cerr << "},"; }
template<typename x> void _print(x& t) { cerr << "{"; for (int i = 0;i < (int)t.size();i++) { _print(t[i]); if (i < (int)t.size() - 1) cerr << ", "; } cerr << "}"; }
template<typename x, typename... y> void _print(x a, y... b) { _print(a);if (sizeof...(b)) cerr << ", ";_print(b...); }
#define dbg(x...) cerr<<"["<<#x<<"] = [";_print(x);cerr<<"]\n";

int test;
const int MXN = 1e5 * 3;
ll a[MXN], n, b;
vl segments[600];
 
ll query(ll l, ll r, ll x){
    ll res = 0, ls = l / b, rs = r / b;
    if(ls == rs){
        for(ll i = l; i < r + 1; i++) res += (a[i] >= x);
        return res;
    } 
 
    for(ll i = l; i < ls * b + b; i++) res += (a[i] >= x);
    for(ll i = rs * b; i < r + 1; i++) res += (a[i] >= x);
    for(ll i = ls + 1; i < rs; i++){
        res += b - (ll)((lower_bound(segments[i].begin(), segments[i].end(), x)) - segments[i].begin());
    }
    return res;
}


void solve() {

    cin >> n;
    ll temp = 1;
    for(ll i = 1; i * i <= n; i++) temp = i;
    if(temp * temp < n) temp++;
    b = temp;
    F0R(i, 600) if(sz(segments[i])) segments[i].clear();
    FOR(i, 1, n + 1){
        cin >> a[i];
        segments[i / b].pb(a[i]);
    }

    ll ans = 0;

    F0R(i, b + 1) sor(segments[i]);

    FOR(i, 2, n){
        ll x = (i - 1 - query(1, i - 1, a[i])) * (n - i - query(i + 1, n, a[i]) );
        // cout << x << "\n";
        ans += x;
    }

    cout << ans << "\n";


 
}

int main() {
    setIO("");
    int T = 1;
    // cin >> T;
    for (test = 1; test <= T; test++) solve();
    return 0;
}

Compilation message (stderr)

Mountains.cpp: In function 'void setIO(std::string)':
Mountains.cpp:50:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |         freopen((name + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Mountains.cpp:51:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 2
• Subtask 2: 0 / 4
• Subtask 3: 0 / 9
• Subtask 4: 36 / 36
• Subtask 5: 28 / 28
• Subtask 6: 0 / 9
• Subtask 7: 0 / 12