代码如下,我好像已经看到GAS爆炸的一幕了? ``` //按dna大小排列的链表 mapping(uint256 => uint256) private mNextStudents; //链表的头 uint256 private constant GUARD = 10000; constructor() public { mNextStudents[GUARD] = GUARD; } //prevTokenid.dna大于等于_newDna且_newDna>_nextTokenid.dna function _verifyIndex( uint256 _prevTokenid, uint256 _newDna, uint256 _nextTokenid ) private view returns (bool) { return (_prevTokenid == GUARD || mTigers[_prevTokenid].dna >= _newDna) && (_nextTokenid == GUARD || _newDna > mTigers[_nextTokenid].dna); } //遍历寻找当前插入位置 function _findIndex(uint256 _newDna) private view returns (uint256) { uint256 tokenid = GUARD; while (true) { if (_verifyIndex(tokenid, _newDna, mNextStudents[tokenid])) { return tokenid; } tokenid = mNextStudents[tokenid]; } } //添加NFT链表 function _addTiger(uint256 _tokenid) private { uint256 tokenid = _findIndex(mTigers[_tokenid].dna); //指向tokenid原先指向的id mNextStudents[_tokenid] = mNextStudents[tokenid]; //tokenid指向当前ID mNextStudents[tokenid] = _tokenid; } //获取排名 function _getTop(uint256 _top) internal view virtual returns (uint256[] memory _res) { _res = new uint256[](_top); uint256 tokenid = mNextStudents[GUARD]; for (uint256 i = 0; i < _top; i++) { if (tokenid != GUARD) { _res[i] = tokenid; tokenid = mNextStudents[tokenid]; } else { _res[i] = 999; } } } ```