50 lines
1.8 KiB
Java
50 lines
1.8 KiB
Java
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import java.util.*;
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class KeithNumber
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{
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//user-defined function that checks if the given number is Keith or not
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static boolean isKeith(int x)
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{
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//List stores all the digits of the X
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ArrayList<Integer> terms=new ArrayList<Integer>();
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//n denotes the number of digits
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int temp = x, n = 0;
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//executes until the condition becomes false
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while (temp > 0)
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{
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//determines the last digit of the number and add it to the List
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terms.add(temp%10);
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//removes the last digit
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temp = temp/10;
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//increments the number of digits (n) by 1
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n++;
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}
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//reverse the List
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Collections.reverse(terms);
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int next_term = 0, i = n;
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//finds next term for the series
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//loop executes until the condition returns true
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while (next_term < x)
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{
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next_term = 0;
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//next term is the sum of previous n terms (it depends on number of digits the number has)
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for (int j=1; j<=n; j++)
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next_term = next_term + terms.get(i-j);
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terms.add(next_term);
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i++;
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}
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//when the control comes out of the while loop, there will be two conditions:
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//either next_term will be equal to x or greater than x
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//if equal, the given number is Keith, else not
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return (next_term == x);
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}
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//driver code
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public static void main(String[] args)
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{
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Scanner in = new Scanner(System.in);
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int n = in.nextInt();
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if (isKeith(n))
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System.out.println("Yes, the given number is a Keith number.");
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else
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System.out.println("No, the given number is not a Keith number.");
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}
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}
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