final

AP1403 - WarmUp/src/main/java/Exercises.java

@@ -3,11 +3,17 @@ public class Exercises {
     /*
         complete this function to check if the input number is prime or not
      */
-    public boolean isPrime(long n) {
+    public boolean isPrime(long n)
+    {
         // todo
-        return false;
-    }
+        for (int i = 2; i * i <= n; i++)
+        {
+            if (n%i==0)
+                return false;
 
+        }
+       return true ;
+    }
     /*
         implement an algorithm to find out the index of input number in a fibonacci sequence starting from 0, 1
         e.g. 0, 1, 1, 2, 3, 5, ...
@@ -16,6 +22,18 @@ public boolean isPrime(long n) {
      */
     public long fibonacciIndex(long n) {
         // todo
+        if (n<=0)
+            return -1 ;
+        int x=0 , z=1 , index=0 ;
+        while (x<=n)
+        {
+            if (x==n)
+                return index;
+            int temp=x+z;
+            x=z;
+            z = temp ;
+            index++;
+        }
         return -1;
     }
 
@@ -39,10 +57,31 @@ public long fibonacciIndex(long n) {
      */
     public char[][] generateTriangle(int n) {
         // todo
-        return null;
+        char[][] matrix = new char[n][];
+        for (int a = 0; a< n; a++)
+            matrix[a]= new char [a+1];
+
+        for (int i = 0; i < n; i++)
+            for (int j = 0; j <=i; j++) {
+                if (j == 0 || j == i || i == n - 1)
+                    matrix[i][j] = '*';
+                else
+                    matrix[i][j] = ' ';
+                }
+
+        return matrix;
     }
 
     public static void main(String[] args) {
         // you can test your code here, but then it should be checked with test cases
+        char[][] mat = new Exercises().generateTriangle(5);
+        for (int i=0 ; i<5 ; i++)
+        {
+            for ( int j=0 ; j<=i ; j++ )
+            {
+                System.out.print(mat[i][j]);
+            }
+            System.out.print("\n");
+        }
     }
 }