BianrySearch.java

BianrySearch.java

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+import edu.princeton.cs.algs4.In;
+import edu.princeton.cs.algs4.StdIn;
+import edu.princeton.cs.algs4.StdOut;
+import java.io.FileInputStream;
+import java.util.Arrays;
+
+public class BianrySearch {
+    
+    
+    public static int rank(int k,int[] a){
+        int lo=0;
+        int hi=a.length-1;
+        while(lo<=hi){
+            int mid=(lo+hi)/2;
+            if(k>a[mid]){
+                lo=mid+1;
+            }
+            else if(k<a[mid]){
+                hi=mid-1;
+            }
+            else{
+                return mid;
+            }
+        }
+        return -1;
+    }
+    
+    public static void main(String args[]){
+        
+         FileInputStream ins;
+          //输入重定向
+        try{
+           ins = new FileInputStream("F:\\所有学习的课程资料\\算法\\课本例题代码数据/tinyT.txt");
+        System.setIn(ins);
+        }catch(Exception e){
+            System.out.println(e.toString());
+        }
+        
+        int[] whitelist=In.readInts(args[0]);
+        Arrays.sort(whitelist);
+        while(!StdIn.isEmpty()){
+            int key=StdIn.readInt();
+            if(rank(key,whitelist)<0)
+                StdOut.println(key);
+        }
+    }
+}