oj.uz

Submission #702666

# Submission time Handle Problem Language Result Execution time Memory
702666 2023-02-24T18:04:38 Z speedyArda JJOOII 2 (JOI20_ho_t2) C++14
100 / 100
 16 ms 2272 KB 
#include "bits/stdc++.h"
using namespace std;
const int MAXN = 2e5+5;
int pref_o[MAXN];
// Sol O(nlogn) (Binary search) -> Let's iterate through 'j' chars and apply binary search from their indexes. Let's start by finding kth j and go from there. That means the j we are chosing is the last j and it would be best to get the closest j which makes k times j characters. After that let's apply binary search for first 'i' index. We can apply binary search to 'i' indexes where we know that we can have k times 'i' characters starting from this index. Again it would be best find the closest 'i' character which makes k times 'i' character. After that in the binary search iteration, we need to look whether our 'i' character index is smaller than 'j' index and whether we have k times 'o' character when our last 'j' index and first 'i' index. If we have we can compare our current value with our answer (minimize it) and try to decrease our search space by decreasing first 'i' potential indexes (r = m - 1). Else we try to increase the first 'i' potential indexes (l = m + 1). Since we can have at max n 'j' characters and n 'i' characters our complexity would be O(nlogn).
int main() 
{
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    vector<int> j_idx, i_idx;
    for(int i = 0; i < n; i++)
    {
        pref_o[i] = 0;
        if(i > 0)
            pref_o[i] = pref_o[i - 1];
        if(s[i] == 'J')
            j_idx.push_back(i);
        else if(s[i] == 'O')
            pref_o[i]++;
        else
            i_idx.push_back(i);
        
    }

    int ans = 1e9;
    for(int i = k - 1; i < j_idx.size(); i++)
    {
        int j_dif = j_idx[i] - j_idx[i - (k - 1)] - (k-2) - 1;

        int l = 0, r = i_idx.size() - 1 - k + 1;
        while(l <= r)
        {
            int m = (l + r) / 2; // First i;
            if(i_idx[m] < j_idx[i])
            {
                l = m + 1;
                continue;
            }
            int temp = j_dif + (i_idx[m + k - 1] - i_idx[m] - (k-2) - 1);
            int first_i = i_idx[m];
            int last_j = j_idx[i];
            if(pref_o[first_i] - pref_o[last_j] >= k)
            {
                temp += first_i - last_j - k - 1;
                ans = min(ans, temp);
                r = m - 1;
            } else
                l = m + 1;
            //cout << ans << "  " << j_idx[i] << " " << i_idx[m] << " " << i << " " << m << "\n";
        }

        
    }

    if(ans == 1e9)
        cout << "-1\n";
    else
        cout << ans << "\n";
}

Compilation message

ho_t2.cpp: In function 'int main()':
ho_t2.cpp:28:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |     for(int i = k - 1; i < j_idx.size(); i++)
      |                        ~~^~~~~~~~~~~~~~

Subtask #1
1.0 / 1.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct

Subtask #2
12.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 340 KB Output is correct
21 Correct 0 ms 340 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 1 ms 212 KB Output is correct
24 Correct 1 ms 340 KB Output is correct
25 Correct 1 ms 340 KB Output is correct
26 Correct 0 ms 212 KB Output is correct
27 Correct 0 ms 340 KB Output is correct
28 Correct 1 ms 340 KB Output is correct
29 Correct 0 ms 340 KB Output is correct
30 Correct 1 ms 212 KB Output is correct
31 Correct 0 ms 212 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 0 ms 340 KB Output is correct
35 Correct 0 ms 340 KB Output is correct

Subtask #3
87.0 / 87.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 340 KB Output is correct
21 Correct 0 ms 340 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 1 ms 212 KB Output is correct
24 Correct 1 ms 340 KB Output is correct
25 Correct 1 ms 340 KB Output is correct
26 Correct 0 ms 212 KB Output is correct
27 Correct 0 ms 340 KB Output is correct
28 Correct 1 ms 340 KB Output is correct
29 Correct 0 ms 340 KB Output is correct
30 Correct 1 ms 212 KB Output is correct
31 Correct 0 ms 212 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 0 ms 340 KB Output is correct
35 Correct 0 ms 340 KB Output is correct
36 Correct 12 ms 1760 KB Output is correct
37 Correct 16 ms 2152 KB Output is correct
38 Correct 12 ms 2272 KB Output is correct
39 Correct 10 ms 2272 KB Output is correct
40 Correct 9 ms 2088 KB Output is correct
41 Correct 10 ms 2272 KB Output is correct
42 Correct 12 ms 2092 KB Output is correct
43 Correct 5 ms 1292 KB Output is correct
44 Correct 6 ms 1632 KB Output is correct
45 Correct 8 ms 2100 KB Output is correct
46 Correct 8 ms 2120 KB Output is correct
47 Correct 8 ms 2088 KB Output is correct
48 Correct 9 ms 2272 KB Output is correct
49 Correct 6 ms 1420 KB Output is correct
50 Correct 10 ms 2212 KB Output is correct
51 Correct 9 ms 2144 KB Output is correct
52 Correct 7 ms 1844 KB Output is correct
53 Correct 7 ms 2272 KB Output is correct
54 Correct 9 ms 2268 KB Output is correct
55 Correct 7 ms 2268 KB Output is correct
56 Correct 6 ms 2268 KB Output is correct