Submission #1072279

#	Time	Username	Problem	Language	Result	Execution time	Memory
1072279		vjudge1	Radio Towers (IOI22_towers)	C++17	0 / 100	4069 ms	23756 KiB

towers

#include <bits/stdc++.h>
// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx2")
// #pragma GCC target("popcnt")
using namespace std;
 
using ll = long long;
using ull = unsigned long long;
using lld = long double;
using vi = vector<int>;
using vll = vector<ll>;
using ii = pair<int,int>;
using pll = pair<ll, ll>;
using vii = vector<ii>;
using vpll = vector<pll>;
 
#define endl '\n'
#define all(x) x.begin(),x.end()
#define lsb(x) x&(-x)
#define gcd(a,b) __gcd(a,b)
#define sz(x) (int)x.size()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fls cout.flush()
 
#define fore(i,l,r) for(auto i=l;i<r;i++)
#define fo(i,n) fore(i,0,n)
#define forex(i,r,l) for(auto i=r; i>=l;i--)
#define ffo(i,n) forex(i,n-1,0)

bool cmin(int &a, int b){if(b<a){a=b;return 1;}return 0;}
bool cmax(int &a, int b){if(b>a){a=b;return 1;}return 0;}
void valid(ll in){cout<<((in)?"YES\n":"NO\n");}
ll lcm(ll a, ll b){return (a/gcd(a,b))*b;}
ll gauss(ll n){return (n*(n+1))/2;}
const int LOG = 20;
struct SparseTable{
    vector<vii> sp;
    int n;
    SparseTable() {}
    SparseTable(int n): n(n), sp(n+3, vii(LOG, mp(0,0))) {}
    ii merge(ii a, ii b){
        return {min(a.fi, b.fi), max(a.se,b.se)};
    }
    void build(){
        fore(b, 1, LOG) {
            fo(i, n-(1<<b)+1) {
                sp[i][b] = merge(sp[i][b-1], sp[i+(1<<(b-1))][b-1]);
            }
        }
    }
    ii query(int l,int r) {
        int lg = log2(r-l+1);
        return merge(sp[l][lg], sp[r-(1<<lg)+1][lg]);
    }
};
struct SegTree{
    vi st;
    int n;
    SegTree(int n): n(n), st(4*n+4, 0) {}
    void update(int i,int x) {update(1,0,n-1,i,x);}
    void update(int nodo,int l,int r,int i,int x) {
        if(l == r) st[nodo] = x;
        else {
            int m = (l+r)/2;
            if(i <= m) update(nodo*2, l, m, i, x);
            else update(nodo*2+1, m+1, r, i, x);
            st[nodo] = max(st[nodo*2], st[nodo*2+1]);
        }
    }
    int query(int l,int r) {return query(1, 0, n-1, l, r);} 
    int query(int nodo,int l,int r,int i,int j){
        if(l>j || r<i) return INT_MIN;
        if(l>=i && r<=j) return st[nodo]; 
        int m =(l+r)/2;
        return max(query(nodo*2, l, m, i, j), query(nodo*2+1, m+1, r, i, j));
    }
};
int n;
vi h;
SparseTable qs;
void init(int nn, vi hh){
    n = nn;
    h = hh;
    qs = SparseTable(n);
    fo(i, n) qs.sp[i][0] = {h[i], h[i]};
    qs.build();
}
int max_towers(int l,int r,int d){
    SegTree dp1(n+1), dp2(n+1);
    int ans = 0;
    fore(i, l, r+1){
        // cout << "Indice " << i << '\n';
        dp1.update(i, max(1, dp2.query(i, r)));
        // cout << dp1.query(i, i) << '\n';
        int lb = l, rb = i-1;
        while(lb <= rb){
            int mb = (lb + rb)/2;
            ii mx = qs.query(mb, i-1);
            if(mx.se > h[i]-d) lb = mb+1;
            else rb = mb-1;
        }
        int bst = -1e9;
        if(lb < i) bst = dp1.query(lb, i-1) + 1;
        lb = i+1, rb = r;
        while(lb <= rb) {
            int mb = (lb + rb)/2;
            ii mx = qs.query(i+1, mb);
            if(mx.se > h[i]-d) rb = mb-1;
            else lb = mb+1;
        }
        if(rb > i && dp2.query(rb,rb) < bst) dp2.update(rb, bst);
    }
    return dp1.query(l, r);
}
// void test_case(){
//     int n;
//     cin >> n;
//     vi h(n);
//     fo(i, n) cin >> h[i];
//     init(n, h);
//     int Q;
//     cin >> Q;
//     while(Q--) {
//         int l, r, d;
//         cin >> l >> r >> d;
//         cout << max_towers(l, r, d) << "\n";
//     }
// }

// int main(){cin.tie(0)->sync_with_stdio(0);
//     int t=1;
//     // cin >> t;
//     while(t--)test_case();
// }

Compilation message (stderr)

towers.cpp: In constructor 'SparseTable::SparseTable(int)':
towers.cpp:41:9: warning: 'SparseTable::n' will be initialized after [-Wreorder]
   41 |     int n;
      |         ^
towers.cpp:40:17: warning:   'std::vector<std::vector<std::pair<int, int> > > SparseTable::sp' [-Wreorder]
   40 |     vector<vii> sp;
      |                 ^~
towers.cpp:43:5: warning:   when initialized here [-Wreorder]
   43 |     SparseTable(int n): n(n), sp(n+3, vii(LOG, mp(0,0))) {}
      |     ^~~~~~~~~~~
towers.cpp: In constructor 'SegTree::SegTree(int)':
towers.cpp:61:9: warning: 'SegTree::n' will be initialized after [-Wreorder]
   61 |     int n;
      |         ^
towers.cpp:60:8: warning:   'vi SegTree::st' [-Wreorder]
   60 |     vi st;
      |        ^~
towers.cpp:62:5: warning:   when initialized here [-Wreorder]
   62 |     SegTree(int n): n(n), st(4*n+4, 0) {}
      |     ^~~~~~~
towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:93:9: warning: unused variable 'ans' [-Wunused-variable]
   93 |     int ans = 0;
      |         ^~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 11
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23