Submission #920377

#TimeUsernameProblemLanguageResultExecution timeMemory
920377PanndaData Transfer (IOI19_transfer)C++14
0 / 100
1 ms1112 KiB
#include <bits/stdc++.h> using namespace std; std::vector<int> get_attachment(std::vector<int> source) { int n = source.size(); int xr = 0; for (int i = 0; i < n; i++) { xr ^= source[i] * (i + 1); } int k = n == 63 ? 6 : 8; vector<int> attachment(k + 1); for (int i = 0; i < k; i++) { attachment[i] = xr >> i & 1; } cout << "xor: " << xr << '\n'; attachment[k] = __builtin_popcount(xr) & 1; return attachment; } std::vector<int> retrieve(std::vector<int> data) { int n = data.size(); int k = n == 63 + 7 ? 6 : 8; n -= k + 1; int parity = 0; for (int i = n; i < n + k + 1; i++) { parity = (parity + data[i]) & 1; } if (!(parity & 1)) { int xr = 0; for (int i = n; i < n + k; i++) { xr += data[i] << (i - n); } for (int i = 0; i < n; i++) { xr ^= data[i] * (i + 1); } cout << "corrupted index inferred: " << xr - 1 << '\n'; if (xr > 0) { data[xr - 1] ^= 1; } } return vector<int>(data.begin(), data.end() - k - 1); }
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