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Submission #633479

# Submission time Handle Problem Language Result Execution time Memory
633479 2022-08-22T14:27:17 Z Lawliet Radio Towers (IOI22_towers) C++17
17 / 100
 945 ms 12736 KB 
#include "towers.h"
#include <bits/stdc++.h>

using namespace std;

const int maxl = 20;
const int maxn = 100010;
const int inf = 1000000010;

class SparseTable
{
    public:

        void build(int n, vector<int> v, bool mn = false)
        {
            isMin = mn;

            for(int i = 1 ; i <= n ; i++)
                tab[0][i] = (mn ? -v[i] : v[i]);

            for(int k = 1 ; k < maxl ; k++)
                for(int i = 1 ; i + (1 << k) - 1 <= n ; i++)
                    tab[k][i] = max( tab[k - 1][i] , tab[k - 1][i + (1 << (k - 1))] ); 
        }

        int query(int l, int r)
        {
            if( l > r )
                return (isMin ? inf : -inf);

            int t = 31 - __builtin_clz(r - l + 1);
            int ans = max( tab[t][l] , tab[t][r - (1 << t) + 1] );

            return (isMin ? -ans : ans);
        }

    protected:

        bool isMin;
        int tab[maxl][maxn];
};

int n;

int v[maxn];
int ord[maxn];

SparseTable stV;

vector<int> valleys;

map<int,int> ans;

pair<int,int> getCost(int i, int j)
{
    int peak = stV.query( i + 1 , j - 1 );
    int diff = min( peak - v[i] , peak - v[j] );

    return {diff, i};
}

void findValleys()
{
    v[0] = v[n + 1] = inf;

    for(int i = 1 ; i <= n ; i++)
        if( v[i - 1] > v[i] && v[i] < v[i + 1] ) valleys.push_back( i );

    int num = (int)valleys.size();

    iota( ord , ord + num , 0 );
    sort( ord , ord + num , [&](int i, int j){
        return v[ valleys[i] ] > v[ valleys[j] ];
    });

    multiset<pair<int,int>> allDiffs;

    for(int i = 0 ; i < (int)valleys.size() - 1 ; i++)
        allDiffs.insert( getCost( valleys[i] , valleys[i + 1] ) );

    set<int> alive;

    for(int a: valleys)
        alive.insert( a );

    for(int i = 0 ; i < num - 1 ; i++)
    {
        int t = allDiffs.begin()->first;
        ans[t] = max( ans[t] , num - i );

        int A = allDiffs.begin()->second;
        int B = *alive.upper_bound(A);

        int die = (v[A] < v[B] ? B : A);

        auto it = alive.find(die);
        auto tmp = alive.begin();

        if( it != alive.begin() )
        {
            tmp = it; tmp--;
            allDiffs.erase( allDiffs.find( getCost(*tmp, *it) ) );
        }

        tmp = it; tmp++;

        if( tmp != alive.end() )
            allDiffs.erase( allDiffs.find( getCost( *it , *tmp ) ) );

        alive.erase(die);
        it = alive.lower_bound(die);

        if( it != alive.end() && it != alive.begin() )
        {
            tmp = it; tmp--;
            allDiffs.insert( getCost(*tmp, *it) );
        }
    }
}

void init(int N, vector<int> H) 
{
    n = N;

    H.insert( H.begin() , 0 );
    stV.build( n , H );

    for(int i = 1 ; i <= n ; i++)
        v[i] = H[i];

    findValleys();
}

int max_towers(int L, int R, int D) 
{
    auto t = ans.lower_bound(D);

    if( t == ans.end() )
        return 1;

    return t->second;
}

Subtask #1
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 386 ms 4708 KB 1st lines differ - on the 1st token, expected: '1', found: '2'
2 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 336 KB 1st lines differ - on the 1st token, expected: '13', found: '131'
2 Halted 0 ms 0 KB -

Subtask #3
0 / 12.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 336 KB 1st lines differ - on the 1st token, expected: '13', found: '131'
2 Halted 0 ms 0 KB -

Subtask #4
0 / 14.0

# Verdict Execution time Memory Grader output
1 Incorrect 700 ms 10916 KB 1st lines differ - on the 1st token, expected: '11903', found: '33010'
2 Halted 0 ms 0 KB -

Subtask #5
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 277 ms 2640 KB Output is correct
2 Correct 904 ms 10944 KB Output is correct
3 Correct 834 ms 10944 KB Output is correct
4 Correct 741 ms 12736 KB Output is correct
5 Correct 945 ms 12700 KB Output is correct
6 Correct 785 ms 12696 KB Output is correct
7 Correct 941 ms 12700 KB Output is correct
8 Correct 891 ms 8000 KB Output is correct
9 Correct 858 ms 7968 KB Output is correct
10 Correct 878 ms 8008 KB Output is correct
11 Correct 932 ms 7976 KB Output is correct
12 Correct 78 ms 10944 KB Output is correct
13 Correct 119 ms 12696 KB Output is correct
14 Correct 126 ms 12704 KB Output is correct
15 Correct 23 ms 8008 KB Output is correct
16 Correct 14 ms 8008 KB Output is correct
17 Correct 82 ms 10668 KB Output is correct
18 Correct 77 ms 11004 KB Output is correct
19 Correct 75 ms 11036 KB Output is correct
20 Correct 117 ms 12636 KB Output is correct
21 Correct 114 ms 12720 KB Output is correct
22 Correct 116 ms 12692 KB Output is correct
23 Correct 119 ms 12704 KB Output is correct
24 Correct 14 ms 7984 KB Output is correct
25 Correct 23 ms 7964 KB Output is correct
26 Correct 14 ms 7976 KB Output is correct
27 Correct 15 ms 7968 KB Output is correct
28 Correct 2 ms 464 KB Output is correct
29 Correct 2 ms 464 KB Output is correct
30 Correct 2 ms 476 KB Output is correct
31 Correct 1 ms 464 KB Output is correct
32 Correct 1 ms 464 KB Output is correct
33 Correct 1 ms 336 KB Output is correct
34 Correct 1 ms 464 KB Output is correct
35 Correct 1 ms 464 KB Output is correct
36 Correct 2 ms 464 KB Output is correct
37 Correct 1 ms 464 KB Output is correct
38 Correct 2 ms 464 KB Output is correct
39 Correct 2 ms 464 KB Output is correct
40 Correct 1 ms 336 KB Output is correct
41 Correct 1 ms 464 KB Output is correct
42 Correct 1 ms 336 KB Output is correct
43 Correct 1 ms 464 KB Output is correct

Subtask #6
0 / 19.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 336 KB 1st lines differ - on the 1st token, expected: '13', found: '131'
2 Halted 0 ms 0 KB -

Subtask #7
0 / 23.0

# Verdict Execution time Memory Grader output
1 Incorrect 386 ms 4708 KB 1st lines differ - on the 1st token, expected: '1', found: '2'
2 Halted 0 ms 0 KB -