远景面试，凉凉

import java.util.Scanner; public class tohex {
    String tohex(int num){
      if(num >=0){  return transe(num);
          }else{ return transe((long) Math.pow(16,8)+num);
        }
    }
    String transe(long num){
        StringBuffer s = new StringBuffer(); long temp = 0;  while (num!=0){
            temp = num%16;
            s.append(sixteen(temp));
            num = (num-temp)/16;
        } return s.reverse().toString();
    }
    String sixteen(long num){ if(num <= 9 && num >= 0) return (num +"");  else  return (char)(num - 10 + 'A') +"";
    } public static  void  main(String[] args){
        tohex t = new tohex();
        Scanner in = new Scanner(System.in);  int n = in.nextInt();
        System.out.println(t.tohex(n));
    }
}

import java.util.Scanner; public class Upperbound {  public int upper2(int num){  int k = (int) Math.ceil(Math.log(num)/Math.log(2)); return (int) Math.pow(2,k);
    }  public static void main(String[] args){
        Upperbound u = new Upperbound();
        Scanner in = new Scanner(System.in);  int n = in.nextInt();
        System.out.println(u.upper2(n));
    }
}

import java.util.ArrayList; //插入的边的类 class MGraph { /*图的邻接矩阵表示*/  int vexs; //图中结点数目  char data[]; //存放结点数据  int [][]weight; //存放边  public MGraph(int ve){  vexs=ve; data=new char[ve]; weight=new int[ve][ve];}
} //邻接矩阵类 public class MyAdjGraphic { /*创建图的邻接矩阵*/    public void CreateGraph(MGraph graph,int vexs,char data[],int [][]weight){  int i,j; for(i=0;i<vexs;i++){
                graph.data[i]=data[i];
   for(j= 0;j<vexs;j++){
                    graph.weight[i][j]=weight[i][j];
                }
            }
        }  public void Prim(MGraph graph,int v){ /*graph为图的邻接矩阵表示，v为起始顶点*/    int visited[]=new int[graph.vexs]; // visited[]标记结点是否被访问过 
       for(int i=0;i<graph.vexs;i++){ //初始化visited[] 
       visited[i]=0;
          }
          visited[v]=1;  int h1=-1,h2=-1; //记录边的弧尾和弧头    int minweight=10000;//minweight记录最小权重    for(int k=1;k<graph.vexs;k++){ //vexs个顶点，最小生成树中有vexs-1条边     for(int i=0;i<graph.vexs;i++){ //i顶点表示被访问过的顶点    for(int j=0;j<graph.vexs;j++){ // j顶点表示未被访问过的顶点 
       if(visited[i]==1 && visited[j]==0 && graph.weight[i][j]<minweight){ //寻找已访问的顶点与未访问的定点间的权值最小的边 
       minweight=graph.weight[i][j];
                            h1=i;
                            h2=j;
                        }
                    }
                }
                System.out.println("边<"+graph.data[h1]+","+graph.data[h2]+"> 权值："+minweight);
                visited[h2]=1; //标记h2被访问过  minweight=10000;
            }
        } public static void main(String args[]){ char []data=new char[]{'A','B','C','D','E'}; int vexs=data.length; int [][]weight=new int[][]{
                    {10000,4,8,5,10000},
                    {4,10000,3,10000,7},
                    {8,3,10000,6,6},
                    {5,10000,6,10000,9},
                    {10000,7,6,9,10000}
            };
            MGraph graph=new MGraph(vexs);
            MyAdjGraphic mt=new MyAdjGraphic();
            mt.CreateGraph(graph,vexs,data,weight);
            mt.Prim(graph, 0);
        }
}

with open("/tmp/foo.txt") as file:
    data = file.read()

class Sample: def __enter__(self): print "In __enter__()" return "Foo" def __exit__(self, type, value, trace): print "In __exit__()" def get_sample(): return Sample()
 
with get_sample() as sample: print "sample:", sample

with context_manager():  
      1/0      
integer division or modulo by zero 

def fun_var_args(farg, *args):      print "arg:", farg      for value in args:          print "another arg:", value    fun_var_args(1, "two", 3) # *args可以当作可容纳多个变量组成的list  result: [python]  arg: 1  another arg: two  another arg: 3

def fun_var_kwargs(farg, **kwargs): 
    print "arg:", farg 
    for key in kwargs: 
        print "another keyword arg: %s: %s" % (key, kwargs[key]) 
 
 
fun_var_kwargs(farg=1, myarg2="two", myarg3=3) # myarg2和myarg3被视为key， 感觉**kwargs可以当作容纳多个key和value的dictionary 
result:
[python] 
arg: 1 
another keyword arg: myarg2: two 
another keyword arg: myarg3: 3 

		

			
			

				
public class Singleton { private static Singleton instance; private Singleton (){} public static synchronized Singleton getInstance() { if (instance == null) {  
        instance = new Singleton();  
    } return instance;  
    }  

} 
https://blog.csdn.net/column/details/jason0539-shejimoshi.html