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Submission #168680

# Submission time Handle Problem Language Result Execution time Memory
168680 2019-12-15T09:20:29 Z dolphingarlic Vještica (COCI16_vjestica) C++14
0 / 160
 2000 ms 1016 KB 
/*
COCI 2016 Vjestica
- Firstly, notice that N is very small. This implies that we should use a bitmask
- For each mask, we split the active words into 2 groups and solve recursively for those
- solve(mask) = min(solve(A) + solve(B)) where A + B = mask, A & mask == A, B & mask == B, and A & B == 0
- Complexity: O(N log N * 2^N)
*/

#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
typedef long long ll;
using namespace std;

int n;
map<char, int> cnt[16];

int solve(int mask) {
    int ans = INT_MAX, common = 0;

    if (!mask) return 0;

    // cout << mask << ": ";

    map<char, int> diff;
    for (char i = 'a'; i <= 'z'; i++) {
        diff[i] = INT_MAX;
        FOR(j, 0, n) if (mask & (1 << j)) diff[i] = min(diff[i], cnt[j][i]);
        common += diff[i];
    }
    FOR(i, 0, n) {
        if (mask & (1 << i)) {
            if (diff == cnt[i]) mask -= (1<<i);
            else for (char j = 'a'; j <= 'z'; j++) cnt[i][j] -= diff[j];
        }
    }

    // cout << mask << ' ' << common << '\n';

    if (!mask) return common;

    FOR(i, (common == 0), mask) {
        if ((mask & i) == i) ans = min(ans, solve(i) + solve(mask - i));
    }

    FOR(i, 0, n) {
        if (mask & (1 << i)) {
            for (char j = 'a'; j <= 'z'; j++) cnt[i][j] += diff[j];
        }
    }
    return ans + common;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n;
    FOR(i, 0, n) {
        for (char j = 'a'; j <= 'z'; j++) cnt[i][j] = 0;
        string s;
        cin >> s;
        for (char j : s) cnt[i][j]++;
    }
    cout << solve((1 << n) - 1) + 1;
    return 0;
}

Subtask #1
0 / 160.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2071 ms 376 KB Time limit exceeded
2 Execution timed out 2059 ms 376 KB Time limit exceeded
3 Execution timed out 2061 ms 376 KB Time limit exceeded
4 Execution timed out 2057 ms 376 KB Time limit exceeded
5 Execution timed out 2068 ms 376 KB Time limit exceeded
6 Execution timed out 2050 ms 632 KB Time limit exceeded
7 Execution timed out 2077 ms 884 KB Time limit exceeded
8 Execution timed out 2077 ms 1016 KB Time limit exceeded
9 Execution timed out 2061 ms 880 KB Time limit exceeded
10 Execution timed out 2066 ms 888 KB Time limit exceeded