Submission #629484

#	Time	Username	Problem	Language	Result	Execution time	Memory
629484		arnold518	Radio Towers (IOI22_towers)	C++17	23 / 100	4046 ms	5428 KiB

towers

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 1e5;

int N, H[MAXN+10];

struct SEG
{
    int tree[MAXN*4+10];
    void init(int node, int tl, int tr)
    {
        if(tl==tr)
        {
            tree[node]=H[tl];
            return;
        }
        int mid=tl+tr>>1;
        init(node*2, tl, mid);
        init(node*2+1, mid+1, tr);
        tree[node]=max(tree[node*2], tree[node*2+1]);
    }
    int query(int node, int tl, int tr, int l, int r)
    {
        if(r<tl || tr<l) return 0;
        if(l<=tl && tr<=r) return tree[node];
        int mid=tl+tr>>1;
        return max(query(node*2, tl, mid, l, r), query(node*2+1, mid+1, tr, l, r));
    }
}seg;

void init(int _N, vector<int> _H)
{
    N=_N;
    for(int i=1; i<=N; i++) H[i]=_H[i-1];
    seg.init(1, 1, N);
}

int max_towers(int L, int R, int D)
{
    L++; R++;

    vector<pii> V;
    vector<int> V2;
    for(int i=L; i<=R; i++) V.push_back({H[i], i});
    sort(V.begin(), V.end());
    
    set<int> S;
    for(auto it : V)
    {
        auto pt=S.lower_bound(it.second);
        bool flag=true;
        if(pt!=S.end())
        {
            int l=it.second, r=*pt;
            if(seg.query(1, 1, N, l, r)-D<it.first) flag=false;
        }
        if(pt!=S.begin())
        {
            int l=*prev(pt), r=it.second;
            if(seg.query(1, 1, N, l, r)-D<it.first) flag=false;
        }
        if(flag) S.insert(it.second), V2.push_back(it.second);
    }
    return S.size();
}

Compilation message (stderr)

towers.cpp: In member function 'void SEG::init(int, int, int)':
towers.cpp:23:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   23 |         int mid=tl+tr>>1;
      |                 ~~^~~
towers.cpp: In member function 'int SEG::query(int, int, int, int, int)':
towers.cpp:32:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   32 |         int mid=tl+tr>>1;
      |                 ~~^~~

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