// SPDX-License-Identifier: Unlicensed pragma solidity ^0.8.17; import "../interfaces/IPuzzle.sol"; /// @title what are buckets? /// @author waldenyan.eth contract WhatAreBuckets is IPuzzle { uint256 public constant PRIMES = 0x20305070b0d1113171d1f25292b2f353b; uint256 public constant numPrimes = 17; /// @inheritdoc IPuzzle function name() external pure returns (string memory) { return unicode"what are buckets?"; } function work(uint256 state, uint8 op) internal pure returns (uint256) { if (op >> 2 == 0) { if ((op & 2) == 2) { state <<= 8; } state &= 0xffffff00ff; if ((op & 1) == 1) { state |= (state >> 16) & 0xff00; } if ((op & 2) == 2) { state >>= 8; } } else if ((op & 5) == 4) { if ((op & 2) == 2) { state = (state & 0xff00ff00) >> 8 | (state & 0x00ff00ff) << 8; } uint256 flow0 = (state >> 8) & 0xff; uint256 flow1 = ((state >> 16) & 0xff) - (state & 0xff); uint256 flow = flow0 > flow1 ? flow1 : flow0; state -= flow << 8; state += flow; if ((op & 2) == 2) { state = (state & 0xff00ff00) >> 8 | (state & 0x00ff00ff) << 8; } } return state; } function workAll(uint256 state, uint256 commands) internal pure returns (uint256) { for (uint256 i = 0; i < 85; i++) { state = work(state, uint8(commands >> (i * 3)) & 7); } return state; } /// @inheritdoc IPuzzle function generate(address _seed) external pure returns (uint256) { uint256 seed = uint256(keccak256(abi.encodePacked(_seed))); uint256 tmp = seed; uint256 numPairs = numPrimes * (numPrimes - 1); while (tmp > 0) { uint256 v = tmp % numPairs; tmp /= numPairs; uint256 a = v % numPrimes; uint256 b = v / numPrimes; if (b >= a) b += 1; uint256 prime1 = (PRIMES >> (a << 3)) & 0xff; uint256 prime2 = (PRIMES >> (b << 3)) & 0xff; if ( (prime1 + 1) % prime2 == 0 || (prime2 + 1) % prime1 == 0 || (prime1 - 1) % prime2 == 0 || (prime2 - 1) % prime1 == 0 ) { continue; } return workAll((prime1 << 24) | (prime2 << 16), seed); } // It's your lucky day! return 1; } /// @inheritdoc IPuzzle function verify(uint256 _start, uint256 _solution) external pure returns (bool) { return workAll(_start, _solution ^ uint256(keccak256(abi.encodePacked(_start)))) & 0xffff == 1; } }

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