Submission #1279226

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279226		vuquangsang	Index (COCI21_index)	C++20	110 / 110	668 ms	25760 KiB

index

/* Vu Quang Sang from Le Khiet High School for Gifted */
#include <bits/stdc++.h>
using namespace std;

#define     lg(x) __lg(x)
#define     alla(a,n) a+1,a+n+1
#define     el "\n"
#define     all(x) x.begin(),x.end()
#define     pb push_back
#define     ll long long
#define     fi first
#define     se second
#define     Mask(i) (1ll<<(i))
#define     c_bit(i) __builtin_popcountll(i)
#define     fr(i,a,b) for(int i = (a), _b = (b); i <= _b; i++)
#define     frd(i,a,b) for(int i = (a), _b = (b); i >= _b; i--)
#define     REP(i, a, b) for(int i = (a), _b = (b); i < _b; i++)

const ll sm = 1e9+7;
const long long inf = 1e18+7;
const ll base = 311;
const ll BLOCK = 320;
const int dx[5] = {0, -1, 1, 0 , 0};
const int dy[5] = {0, 0, 0, -1, 1};

struct node{ll x,y;};
struct pll{ll fi,se;};
template <class T> bool maxi(T &x, T y) { if(x < y) { x = y ; return true ;} return false;}
template <class T> bool mini(T &x, T y) { if(x > y) { x = y ; return true ;} return false;}
ll gcd(ll a, ll b) {return __gcd(a, b);}
ll lcm(ll a, ll b) {return a/gcd(a, b)*b;}

const int N = 2e5 + 2;
int n, q, a[N];
node Q[N];
void input()
{
    cin >> n >> q; fr(i, 1, n) cin >> a[i];
    fr(i, 1, q) cin >> Q[i].x >> Q[i].y;
}
namespace sub1
{

    int L[N], R[N], ans[N];
    vector<int> qry[N];
    vector<int> pos[N];
//    vector<int> st[4 * N];
//
//    vector<int> MER(vector<int> a, vector<int> b)
//    {
//        vector<int> res(a.size() + b.size());
//        merge(all(a), all(b), res.begin());
//        return res;
//    }
//    void build(int id, int l, int r)
//    {
//        if(l == r) {
//            st[id].pb(a[l]);
//            return;
//        }
//        int mid = (r + l) >> 1;
//        build(id << 1, l, mid);
//        build(id << 1 | 1, mid + 1, r);
//        st[id] = MER(st[id << 1], st[id << 1 | 1]);
//    }
//    int get(int id, int l, int r, int u, int v, int val)
//    {
//        if(r < u || v < l) return 0;
//        if(u <= l && r <= v) {
//            return st[id].end() - lower_bound(all(st[id]), val);
//        }
//        int mid = (r + l) >> 1;
//        return get(id << 1, l, mid, u, v, val) + get(id << 1 | 1, mid + 1, r, u, v, val);
//    }

    int bit[N + 2];

    void upd(int x, int v)
    {
        for(;x <= 2e5; x += x & -x) bit[x] += v;
    }
    int get(int x)
    {
        int ans = 0 ;
        for(; x >= 1; x -= x & -x) ans += bit[x];
        return ans;
    }
    int get(int l, int r)
    {
        return get(r) - get(l - 1);
    }
    void slv()
    {
        fr(i, 1, q) L[i] = 1, R[i] = Q[i].y - Q[i].x + 1;
        fr(i, 1, n) pos[a[i]].pb(i);
//        build(1, 1, n);
        while(1){
            bool ok = 0;
            fr(i, 1, q) if(L[i] <= R[i]) {
                ok = 1;
                qry[(L[i] + R[i]) / 2].pb(i);
            }
            if(!ok) break;
//            voi 1 doan l -> r dem xem co bao nhieu so >= val, upd vi tri bang 1, dem so vi tri
            frd(val, n, 1){
                for(int x : pos[val]) upd(x, 1);
                for(int id : qry[val]) {
                    int mid = (L[id] + R[id]) / 2;
                    int l = Q[id].x, r = Q[id].y;
                    if(get(l, r) >= val) {
                        ans[id] = val;
                        L[id] = mid + 1;
                    }
                    else R[id] = mid - 1;
                }
            }
            fr(i, 1, 2e5) bit[i] = 0;
            fr(i, 1, n) qry[i].clear();
        }
        fr(i, 1, q) cout << ans[i] << el;
    }
}
namespace sub2
{
    void slv()
    {

    }
}

main()
{
    #define TASK "task"
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    if( fopen( TASK".INP", "r") ){
        freopen( TASK".INP", "r", stdin);
        freopen( TASK".OUT", "w", stdout);
    }
    bool qs = 0;
    ll mtt = 1;
    if(qs) cin >> mtt;
    fr(i, 1, mtt){
        input();
        sub1::slv();
    //    sub2::slv();
    }
}

Compilation message (stderr)

index.cpp:131:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  131 | main()
      | ^~~~
index.cpp: In function 'int main()':
index.cpp:138:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  138 |         freopen( TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
index.cpp:139:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  139 |         freopen( TASK".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 50 / 50