【leetCode】【javascript】997. Find the Town Judge找到小镇的法官

2024年6月10日 111次阅读

题目描述：

In a town, there are N people labelled from 1 to N.  There is a rumor that one of these people is secretly the town judge.

If the town judge exists, then:

  1. The town judge trusts nobody.
  2. Everybody (except for the town judge) trusts the town judge.
  3. There is exactly one person that satisfies properties 1 and 2.

You are given trust, an array of pairs trust[i] = [a, b] representing that the person labelled a trusts the person labelled b.

If the town judge exists and can be identified, return the label of the town judge.  Otherwise, return -1.

解释一下：这个题目的意思其实就是，这个小镇有n个，所有人除了法官都相信法官，但是法官不相信任何人。这个题用到了数据结构的图，这里我用邻接表表示无向图

代码如下：

var findJudge = function(N, trust) {
    if(N === 1){
       return 1
    }
     var vertices = [];//存储顶点
    var adjList = {}//存储边
    var ans= '';
    var total = {}
    //添加顶点
    this.addVertex = function(v){
         vertices.push(v);
       total[v]={};
       total[v].count = 0;
       adjList[v] = []
    }
    //添加边
    this.addEdge = function(a,b){
        adjList[b].push(a)
    }
    
    for(var i=1;i<=N;i++){
        addVertex(i)
    }
    for(var j=0;j<trust.length;j++){
        var a = trust[j][0];
        var b = trust[j][1];
        addEdge(a,b)
    }
    
    for(var i=0;i<vertices.length;i++) {
       var dingdian = vertices[i];
       
       var bian = adjList[dingdian];
       if(bian.length>0&&bian.length === N-1){
           ans = dingdian
       }
        for(var j=0;j<bian.length;j++){
            ++total[bian[j]].count;   
        }
   }
    if(ans === ''||total[ans].count !== 0){
        return -1
    }
    else{
        return ans
    }
};

代码有点乱，先凑合吧，有时间还得再修改

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