Unit 10: Sorting/Searching/Recursion

Transcription

1 Unit 10: Sorting/Searching/Recursion Exercises 1. If you search for the value 30 using a linear search, which indices of the 2. If you search for the value -18 using a binary search, which indices of the 3. If you search for the value 90 using a binary search, which indices of the AP CS A Index Value If you search for the value -55 using a binary search, which indices of the 5. If you search for the value 15 using a binary search, which indices of the 6. If you search for the value 2 using a linear search, which indices of the 7. If you search for the value -122 using a linear search, which indices of the Index Value Is a zero, positive, or negative number 9. Is a zero, positive, or negative number 10. Is a zero, positive, or negative number 11. Is a zero, positive, or negative number 12. Is a zero, positive, or negative number 13. Is a zero, positive, or negative number System.out.println( "cow".compareto( "horse" )); System.out.println( "zoo".compareto("zebra" ) ); System.out.println( "LAX".compareTo( "PHL" )); System.out.println( "PHL".compareTo( "LAX" )); System.out.println( "b".compareto( "boo" ) ); System.out.println( "eels".compareto( "eel" ) ); Note. I will not test you on whether a lower case letter is greater than the corresponding upper case letter or whether the character 3 is greater or less than some other string.

2 14. Selection Sort. An array has the values shown in the second column. Complete the table below to Selection Sort. An array has the values shown in the second column. Complete the table below to Selection Sort. An array has the values shown in the second column. Complete the table below to Insertion Sort. An array has the values shown in the second column. Complete the table below to

3 18. Insertion Sort. An array has the values shown in the second column. Complete the table below to Insertion Sort. An array has the values shown in the second column. Complete the table below to If a particular recursive method never terminates, say so. 20. What is the value of z? int z = mm( 3 ); 21. What is the value of y? int y = mm( 5 ); public int mm( int n ){ if ( n <= 1 ) return 1; return n * mm( n - 1 ); 22. What does pop( 8, 8 ) display? 23. What does pop( 13, 13 ) display? 24. What is the value of z? int z = abc( 3 ); 25. What is the value of y? int y = abc( 6 ); public void pop( int n, int f ) { if ( n <= 0 f <= 0 ) return; if ( n % f == 0 ) System.out.print( f + ", " ); pop( n, f - 1 ); public int abc( int w ) { if ( w < 0 ) return w - abc( w - 2 );

4 26. What is the value of a? int a = rec( -4 ); 27. What is the value of b? int b = rec( 2 ); public int rec( int x ){ if ( x <= 0 ) return x; return x + rec( x + 1 ); 28. What is public static void main(string[] args) { for ( int k = 1; k <= 8; k++ ) System.out.print( fred(k) + " " ); public static int fred( int n ) { if ( n <= 2 ) return 1; return fred( n- 1 ) + fred( n-2 ); 29. What does ex1( 78 ) display? 30. What does ex1( 1234 ) display? public void ex1( int x ){ System.out.print( x%10 + " " ); if ( x/10!= 0 ) ex1( x/10 ); System.out.print( x%10 + " " ); 31. What is the value of a? int a = g(8, 16) 32. What is the value of b? int b = g(12, 9) 33. What is the significance of the number that this method ultimately returns? public int g( int x, int y ){ if ( x%y == 0) return y; return g( y, x%y ); /* This method implements an algorithm from Euclid from about 200 B.C. */ 34. What does rr( 3 ) return? 35. What does rr( 6 ) return? public int rr( int n ){ if ( n <= 0 ) return n + rr( n - 1);

5 36. What does this display? public static void main(string[] args) { int [] list1 = { 4, 8, 1 ; System.out.println( a1(list1) ); int [] list2 = { 6, -2, 5, 3 ; System.out.println( a1(list2) ); public static int a1( int [] a ){ return a1( a, 0 ); private static int a1( int [] a, int i ){ if ( i >= a.length ) return a[i] + a1( a, i+1 ); 37. What is 38. Describe, in general terms, what the first m2 method returns. public static void main(string[] args) { int [] a = { 2, 24, 37, 38, 44, 71 ; int x = m2( 17, a ); System.out.println( x ); x = m2( 44, a ); System.out.println( x ); public static int m2( int val, int [] a ){ return m2( val, a, 0, a.length-1 ); private static int m2( int val, int [] a, int n1, int n2 ) { if ( n1 > n2 ) return -1; int num = (n1 + n2)/2; if ( a[ num ] == val ) return num; if ( a[ num ] < val ) return m2( val, a, num + 1, n2 ); return m2( val, a, n1, num - 1 );