add binary search function iterative

Author: joney000

Algorithms/BinarySearch.java

@@ -0,0 +1,70 @@
+/* package joney_000 */
+
+import java.util.*;
+import java.lang.*;
+import java.io.*;
+import java.math.*;
+
+
+ public class Solution
+
+ {
+
+  public static void main(String[] args)throws Exception
+
+    {  
+	
+	/*  	BufferedReader br=new BufferedReader(new FileReader("input.txt"));
+        BufferedWriter out=new BufferedWriter(new FileWriter("output.txt"));
+    */               
+
+       BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
+       BufferedWriter out=new BufferedWriter(new OutputStreamWriter(System.out));
+    
+        
+			int t = Integer.parseInt(br.readLine());
+			long arr[] = new long[1000001];
+			
+			for (long i=1;i<=1000000;i++){
+			  arr[(int)i]=(i*(i+1)*(2*i+1))/6;
+			}
+
+			for (int test=0;test<t;test++){
+				long x = Long.parseLong(br.readLine());
+			  int idx = Arrays.binarySearch(arr,1,1000000+1,x); // [L..R] = Arrays.binarySearch(arr,l,r+1,key);
+			  if(idx < 0){
+			    idx = -idx;
+			    idx -= 2;
+			  }
+	 		  long ans = idx ;
+			  out.write(""+ans+"\n");
+			  out.flush();          
+			}     
+        	
+        
+    }//end of public static void main();
+	public static boolean isPrime(long n)throws Exception{
+		if(n==2||n==3)return true;
+		for(int i=2;i<=Math.sqrt(n);i++){
+			if(n%i==0)return false;
+		}
+	return true;
+	}
+	public static long gcd(long a, long b)throws Exception{
+		if(b==0)return a;
+		return gcd(b,a%b);
+	}
+	public static long lcm(long a, long b)throws Exception{
+		if(b==0||a==0)return 0;
+		return (a*b)/gcd(a,b);
+	}
+	public static long pow(long a,long b,long mod)throws Exception{
+		if(b==1)return a%mod;
+		if(b==0)return 1;
+		long ans=pow(a,b/2,mod);
+		ans=(ans*ans)%mod;
+		if(b%2!=0)ans=(ans*a)%mod;
+	
+		return ans;
+	}
+ } /