Submission #517053

#	Time	Username	Problem	Language	Result	Execution time	Memory
517053		Be_dos	Table Tennis (info1cup20_tabletennis)	C++17	100 / 100	1675 ms	956136 KiB

tabletennis

#include <iostream>
#include <cmath>
#include <cctype>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <deque>
#include <stack>
#include <unordered_set>
#include <sstream>
#include <cstring>
#include <iomanip>
#include <queue>
#include <unordered_map>
#include <random>
#include <cfloat>
#include <chrono>
#include <bitset>
#include <complex>
#include <immintrin.h>
#include <cassert>

#define BASE 1'000'000'005
#define MOD 1'000'000'007

int32_t* base_powers;

int32_t get_hash(int32_t* hashes, int32_t start, int32_t len) {
    return (hashes[start + len] - ((int64_t)hashes[start] * base_powers[len]) % MOD + MOD) % MOD;
}

int32_t get_matches(int32_t n, int32_t* arr1, int32_t* arr2, int32_t max_missed,
                    int32_t* hashes_left, int32_t* hashes_right) {
    int32_t ans = 0;
    int32_t ptr1 = 0, ptr2 = 0;
    int32_t missed = 0;
    while(ptr1 < n && ptr2 < n) {
        if(arr1[ptr1] == arr2[ptr2]) {
            int32_t left = 1, right = n - std::max(ptr1, ptr2) + 1;
            while(right - left > 1) {
                int32_t m = (left + right) / 2;
                if(get_hash(hashes_left, ptr1, m) == get_hash(hashes_right, ptr2, m))
                    left = m;
                else
                    right = m;
            }
            ans += left;
            ptr1 += left;
            ptr2 += left;
        } else {
            missed++;
            if(missed > max_missed)
                return ans;

            if(arr1[ptr1] < arr2[ptr2])
                ptr1++;
            else
                ptr2++;
        }
    }
    return ans;
}

int main() {
    base_powers = new int32_t[200'000];
    base_powers[0] = 1;
    for(int32_t i = 1; i < 200'000; i++)
        base_powers[i] = ((int64_t)base_powers[i - 1] * BASE) % MOD;

    int32_t n, k;
    std::cin >> n >> k;
    n += k;

    int32_t* arr = new int32_t[n];
    for(int32_t i = 0; i < n; i++)
        std::cin >> arr[i];

    int32_t** per_start = new int32_t*[k + 1];
    int32_t** hashes_start = new int32_t*[k + 1];
    for(int32_t i = 0; i <= k; i++) {
        per_start[i] = new int32_t[n];
        for(int32_t j = 0; j < n; j++)
            per_start[i][j] = arr[j] - arr[i];
        hashes_start[i] = new int32_t[n + 1];
        hashes_start[i][0] = 0;
        for(int32_t j = 1; j <= n; j++)
            hashes_start[i][j] = (hashes_start[i][j - 1] * BASE + per_start[i][j - 1] + 1'000'000'000) % MOD;
    }
    int32_t** per_end = new int32_t*[k + 1];
    int32_t** hashes_end = new int32_t*[k + 1];
    for(int32_t i = 0; i <= k; i++) {
        per_end[i] = new int32_t[n];
        for(int32_t j = 0; j < n; j++)
            per_end[i][j] = arr[n - i - 1] - arr[j];
        std::reverse(per_end[i], per_end[i] + n);

        hashes_end[i] = new int32_t[n + 1];
        hashes_end[i][0] = 0;
        for(int32_t j = 1; j <= n; j++)
            hashes_end[i][j] = (hashes_end[i][j - 1] * BASE + per_end[i][j - 1] + 1'000'000'000) % MOD;
    }

    for(int32_t i = 0; i <= k; i++)
        for(int32_t j = 0;j <= k; j++) {
            int32_t matches = get_matches(n, per_start[i], per_end[j], 2 * k,
                                          hashes_start[i], hashes_end[j]);
            if(matches >= n - k) {
                int32_t true_sum = arr[i] + arr[n - j - 1];
                std::map<int32_t, int32_t> freq;
                for(int32_t p = 0; p < n; p++)
                    freq[arr[p]]++;

                std::vector<int32_t> ans;
                for(int32_t p = 0; p < n; p++)
                    if(arr[p] * 2 < true_sum && freq[true_sum - arr[p]] > 0) {
                        ans.push_back(arr[p]);
                        ans.push_back(true_sum - arr[p]);
                        freq[true_sum - arr[p]]--;
                    } else if(arr[p] * 2 == true_sum && freq[true_sum - arr[p]] > 1) {
                        ans.push_back(arr[p]);
                        ans.push_back(true_sum - arr[p]);
                        freq[true_sum - arr[p]]-=2;
                    }

                ans.resize(n - k);
                std::sort(ans.begin(), ans.end());
                for(int32_t p = 0; p < n - k; p++)
                    std::cout << ans[p] << " ";
                return 0;
            }
        }
    return 0;
}
         

• Subtask 1: 11 / 11
• Subtask 2: 9 / 9
• Subtask 3: 14 / 14
• Subtask 4: 15 / 15
• Subtask 5: 9 / 9
• Subtask 6: 14 / 14
• Subtask 7: 15 / 15
• Subtask 8: 13 / 13