Question

给出以下对象阵容：

var lineup = [
  {
    "Name": "Matt Ryan",
    "Team": "ATL",
    "Position": "QB"
  },{
    "Name": "Devonte Freeman",
    "Team": "ATL",
    "Position": "RB"
  }, {
    "Name": "Jahvid Best",
    "Team": "DET",
    "Position": "RB"
  }, {
    "Name": "Calvin Johnson",
    "Team": "DET",
    "Position": "WR"
  },{
    "Name": "Julio Jones",
    "Team": "ATL",
    "Position":"WR"
  }, {
    "Name": "Julian Edelman",
    "Team": "NE",
    "Position": "WR"
  }, {
    "Name": "Kyle Rudolph",
    "Team": "MIN",
    "Position": "TE"
  }, {
    "Name": "Jordy Nelson",
    "Team": "GB",
    "Position": "WR"
  }, {
    "Name": "Cincinatti Bengals",
    "Team": "CIN",
    "Position": "DST"
  }
];

评估阵容并在有效时返回true，在要求下返回false：

//rule 1: must use 9 players
//rule 2: must use a roster spanning 2 games
//rule 3: Must fit to position requirements
//rule 4: Limit maximum number of players from one team to 4

var validateLineup(lineup){
    var posReq = positionRequirement(lineup);  //checks rule 1 and 3
    var validGames = checkValidGames(lineup); //check rule 2
    var maxPlayers = checkMaxPlayers(lineup); //check rule 4
    return posReq && validGames && maxPlayers;
}

var checkMaxPlayers(lineup){
    var teamDict = [];
    var maxTeam = 0;
    for (var i = 0; i < lineup.length; i++){
      for (var j = 1; j < lineup.length; j++){
        if (lineup[i].Team === lineup[j].Team){
          maxTeam++;
        }
      }
      if (maxTeam > 3) return false;
    }
    return true;
}

var checkValidGames(lineup){
  var arrTeams = [];
  for (var i = 0; i < lineup.length; i++){
    if (!lineup[i].Team in arrTeams ){
      arrTeams.push(lineup[i].Team);
    }
  }
  if (arrTeams.length >= 2) return true;
  else return false;
}

//O(N) time complexity O(1) space
var positionRequirement(lineup){
  var noQB, noRB, noWR, noTE, noDST = 0;
  for (var i = 0; i < lineup.length; i++){
    if (lineup[i].Position === "QB"){
      noQB++;
    }
    else if (lineup[i].Position === "RB"){
      noRB++;
    }
    else if (lineup[i].Position === "WR"){
      noWR++;
    }
    else if (lineup[i].Position === "TE"){
      noTE++;
    }
    else if (lineup[i].Position === "DST"){
      noDST++;
    }
  }

  if (noQB != 1) return false;
  else if (noRB > 3 || noRB < 2) return false;
  else if (noWR > 4 || noWR < 3) return false;
  else if (noTE > 2 || noTE < 1) return false;
  else if (noDST != 1) return false;

  if (noQB+noRB+noWR+noTE+noDST === 9) return true;
  else return false;
}

我相信一切都应该没问题，除非我特别喜欢在一支球队中检查最多球员的功能。如果是任何其他语言，我觉得使用地图会更快，但因为它的javascript，初始化字典然后评估似乎它比只做一个O（N ^ 2）循环要慢。我们将非常感谢代码检查和进一步改进提示

Answer 1

在JavaScript中，对象的工作方式类似于地图。因此，您可以在线性时间内浏览您的数据并与其玩家分享不同的团队。

Answer 2

checkMaxPlayers函数有一个修复程序，我猜每个内部循环之后maxTeam必须重置为0，这是修复程序：

 var checkMaxPlayers(lineup){
    var teamDict = [];
    var maxTeam = 0;
    for (var i = 0; i < lineup.length; i++){
      for (var j = 1; j < lineup.length; j++){
        if (lineup[i].Team === lineup[j].Team){
          maxTeam++;
        }
      }
      if (maxTeam > 4) 
      {
         return false;
      }
      else
      {
        maxTeam=0; 
      }
    }
    return true;
}

Answer 3

使用像字典这样的对象，一次遍历数据，如果不存在，则将团队添加到对象的键中；如果存在，则增加该团队的值。

遍历键列表，如果键值大于4，则返回false。

function checkMaxPlayers(lineup)
{
    var team = [];

    lineup.forEach(el => {
        
        if(Object.keys(team).includes(el.Team))
        {
            team[el.Team]++;
        }
        else
        {
            team[el.Team] = 1;
        }
    });


   for(let key of Object.entries(team))
   {
       if(key[1]>4)
       {
           return false;
       }
   }
   return true;
}

Answer 4

所有 3 个函数都有小问题，这里是每个函数的修复程序。它们现在都使用给定的列表返回 true

//rule 1: must use 9 players
//rule 2: must use a roster spanning 2 games
//rule 3: Must fit to position requirements
//rule 4: Limit maximum number of players from one team to 4

function validateLineup(lineup){
    var posReq = positionRequirement(lineup);  //checks rule 1 and 3
    var validGames = checkValidGames(lineup); //check rule 2
    var maxPlayers = checkMaxPlayers(lineup); //check rule 4
    return posReq && validGames && maxPlayers;
}

//O(N) time complexity O(1) space
function positionRequirement(lineup){
  var noQB = noRB = noWR = noTE = noDST = 0;
  for (var i = 0; i < lineup.length; i++){
    if (lineup[i].Position === "QB"){
      noQB++;
    }
    else if (lineup[i].Position === "RB"){
      noRB++;
    }
    else if (lineup[i].Position === "WR"){
      noWR++;
    }
    else if (lineup[i].Position === "TE"){
      noTE++;
    }
    else if (lineup[i].Position === "DST"){
      noDST++;
    }
  }

  if (noQB != 1) return false;
  else if (noRB > 3 || noRB < 2) return false;
  else if (noWR > 4 || noWR < 3) return false;
  else if (noTE > 2 || noTE < 1) return false;
  else if (noDST != 1) return false;

  if (noQB+noRB+noWR+noTE+noDST === 9) return true;
  else return false;
}

function checkValidGames(lineup){
  var arrTeams = [];
  for (var i = 0; i < lineup.length; i++){
    if (!arrTeams.includes(lineup[i].Team) ){
      arrTeams.push(lineup[i].Team);
    }
  }
  
  if (arrTeams.length >= 2) return true;
  else return false;
}

function checkMaxPlayers(lineup){
    var teamMap = {};
    var maxTeam = 0;
    for (var i = 0; i < lineup.length; i++){
        teamMap[lineup[i].Team] = 0;
    }
    
    for (var i = 0; i < lineup.length; i++){
        teamMap[lineup[i].Team]++;
        if(teamMap[lineup[i].Team] > maxTeam){
          maxTeam = teamMap[lineup[i].Team]
        } 
    }
    
    if (maxTeam > 3) return false;
    return true;
}

使用给定参数验证梦幻足球阵容

4 个答案: