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Submission #646600

# Submission time Handle Problem Language Result Execution time Memory
646600 2022-09-30T09:29:30 Z Elias_Obeid Necklace (Subtask 1-3) (BOI19_necklace1) C++17
85 / 85
 308 ms 492 KB 
#include <bits/stdc++.h>

std::vector<int> kmpString(const std::string &initial_string)
{
    int string_size = (int)initial_string.size();
    std::vector<int> prefix_function(string_size);
    for (int i = 1; i < string_size; ++i)
    {
        int j = prefix_function[i - 1];
        while (j > 0 && initial_string[i] != initial_string[j])
        {
            j = prefix_function[j - 1];
        }

        if (initial_string[i] == initial_string[j])
        {
            ++j;
        }
        prefix_function[i] = j;
    }
    return prefix_function;
}

void getBest(const std::string &S, const std::string &T,
             int &maximum_length, int &indexS, int &indexT, bool reveresedT)
{
    int N = (int)S.size();
    int M = (int)T.size();

    for (int i = 0; i < N; ++i)
    {
        std::string X = S.substr(i) + '#' + T;
        std::string Y = T + '#' + S.substr(0, i);
        std::reverse(Y.begin(), Y.end());

        std::vector<int> prefix_functionX = kmpString(X);
        std::vector<int> prefix_functionY = kmpString(Y);

        int indexX = i, indexY = N - i;
        for (int j = 0; j <= M; ++j)
        {
            int current_length = prefix_functionX[indexY + j] + prefix_functionY[indexX + M - j];
            if (current_length > maximum_length)
            {
                int current_indexS = i - prefix_functionY[indexX + M - j];
                int current_indexT = j - prefix_functionX[indexY + j];
                if (reveresedT)
                {
                    current_indexT = M - 1 - (j + prefix_functionY[indexX + M - j] - 1);
                }
                maximum_length = current_length;
                indexS = current_indexS;
                indexT = current_indexT;
            }
        }
    }
}

int main()
{
    std::string S, T;
    std::cin >> S >> T;

    int maximum_length = 0, indexS = -1, indexT = -1;
    for (int type = 0; type < 2; ++type)
    {
        getBest(S, T, maximum_length, indexS, indexT, static_cast<bool>(type));
        std::reverse(T.begin(), T.end());
    }
    std::cout << maximum_length << std::endl;
    std::cout << indexS << " " << indexT;
    return 0;
}

Subtask #1
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 296 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 296 KB Output is correct
6 Correct 7 ms 296 KB Output is correct
7 Correct 5 ms 296 KB Output is correct
8 Correct 6 ms 340 KB Output is correct
9 Correct 5 ms 340 KB Output is correct
10 Correct 4 ms 340 KB Output is correct
11 Correct 5 ms 340 KB Output is correct
12 Correct 5 ms 296 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 296 KB Output is correct
6 Correct 7 ms 296 KB Output is correct
7 Correct 5 ms 296 KB Output is correct
8 Correct 6 ms 340 KB Output is correct
9 Correct 5 ms 340 KB Output is correct
10 Correct 4 ms 340 KB Output is correct
11 Correct 5 ms 340 KB Output is correct
12 Correct 5 ms 296 KB Output is correct
13 Correct 279 ms 368 KB Output is correct
14 Correct 241 ms 492 KB Output is correct
15 Correct 308 ms 376 KB Output is correct
16 Correct 253 ms 388 KB Output is correct
17 Correct 213 ms 380 KB Output is correct
18 Correct 201 ms 380 KB Output is correct
19 Correct 221 ms 392 KB Output is correct
20 Correct 256 ms 376 KB Output is correct
21 Correct 251 ms 380 KB Output is correct