2005 11 14 1 1.1 2 1.2 (search:) [1] () 2 (linear search) (sequential search) 1
2.1 2.1.1 List 2-1(p.37) 1 1 13 n<num&&a[n]!=x n () n/2 n O(n) 2.1.2 List 2-1(p.37) 1 1 2
1: 2.1.3 1 List 2-1(p.37-38) 3
1: 1 #include <s t d i o. h> 2 #include <s t d l i b. h> 3 #include <time. h> 4 5 #define NOT FOUND ( 1) 6 #define N ( 1 0 ) 7 8 int l i n e a r s e a r c h ( int x, int a, int num) 9 { 10 int n=0; 11 12 / / 13 while ( n<num&&a [ n ]!= x ) 14 n++; 15 16 i f ( n<num) 17 return n ; 18 19 return NOT FOUND; 20 } 21 22 int main ( void ) 23 { 24 int i, r, array [N ] ; 25 26 srand ( ( unsigned int ) time (NULL) ) ; 27 28 / / 29 p r i n t f ( array ) ; 30 for ( i =0; i <N; i ++) 31 p r i n t f ( [%d ]:% d, i, array [ i ]= rand ()%20); 32 33 p r i n t f ( \ n : ) ; 34 s c a n f ( %d,& i ) ; 35 36 r=l i n e a r s e a r c h ( i, array,n) ; 37 38 i f ( r==not FOUND) 39 p r i n t f ( % d \n, i ) ; 40 else 41 p r i n t f ( %d %d \n, i, r ) ; 42 43 return EXIT SUCCESS ; 44 } 2.2 2.2.1 1 1 13 2 (n<num a[n]!=x) () n<num a[n]!=x] 4
O(n) 2.2.2 List 2-2(p.38-39) 2 2 5
2: 2.2.3 2 List 2-2(p.38-39) 6
2: 1 #include <s t d i o. h> 2 #include <s t d l i b. h> 3 #include <time. h> 4 5 #define NOT FOUND ( 1) 6 #define N ( 1 0 ) 7 8 int s e a r c h ( int x, int a, int num) 9 { 10 int n=0, t ; 11 12 / x / 13 t=a [ num 1]; 14 a [ num 1]=x ; 15 16 / / 17 while ( a [ n ]!= x ) 18 n++; 19 20 a [ num 1]= t ; / / 21 i f ( n<num 1) 22 return n ; / / 23 i f ( x==t ) 24 return n ; / / 25 26 return NOT FOUND; 27 } 28 29 int main ( void ) 30 { 31 int i, r, array [N ] ; 32 33 srand ( ( unsigned int ) time (NULL) ) ; 34 35 / / 36 p r i n t f ( array ) ; 37 for ( i =0; i <N; i ++) 38 p r i n t f ( [%d ]:% d, i, array [ i ]= rand ()%20); 39 40 p r i n t f ( \ n : ) ; 41 s c a n f ( %d,& i ) ; 42 43 r=s e a r c h ( i, array,n) ; 44 i f ( r==not FOUND) 45 p r i n t f ( % d \n, i ) ; 46 else 47 p r i n t f ( %d %d \n, i, r ) ; 48 49 return EXIT SUCCESS ; 50 } 3 7
1/2 1 1 n/2 1 3.1 3.1.1 [left, right] a[left] a[right] n a[0] a[n-1] [0, n 1] mid = (left + right)/2 x a[mid] x x mid a[mic] x [mid + 1, right] x a[mic] x [left, mid 1] x 1 3 12 22 1/2 α 1 n ( ) α 1 n = 1 (1) 2 α α = log 2 n (2) O(log 2 n) 3.1.2 List 2-3(p.41-42) 3 3 8
3: 9
3.1.3 3 List 2-3(p.41-42) 3: 1 #include <s t d i o. h> 2 #include <s t d l i b. h> 3 #include <time. h> 4 5 #define NOT FOUND ( 1) 6 #define N ( 1 0 ) 7 8 int b i n a r y s e a r c h ( int x, int a, int l e f t, int r i g h t ) 9 { 10 int mid ; 11 12 while ( l e f t <=r i g h t ) 13 { 14 mid=( l e f t+r i g h t ) / 2 ; 15 i f ( a [ mid]==x ) 16 return mid ; 17 18 i f ( a [ mid]<x ) 19 l e f t=mid+1; / m i d x / 20 else 21 r i g h t=mid 1; / m i d x / 22 } 23 24 / / 25 return NOT FOUND; 26 } 27 28 int main ( void ) 29 { 30 int i, r, array [N ] ; 31 32 srand ( ( unsigned int ) time (NULL) ) ; 33 34 / / 35 p r i n t f ( array ) ; 36 p r i n t f ( [ 0 ] : % d, array [0]= rand ( ) %3); 37 for ( i =1; i <N; i ++) 38 p r i n t f ( [%d ]:% d, i, array [ i ]= array [ i 1]+rand ()%3); 39 40 p r i n t f ( \ n : ) ; 41 s c a n f ( %d,& i ) ; 42 43 r=b i n a r y s e a r c h ( i, array, 0,N 1); 44 45 i f ( r==not FOUND) 46 p r i n t f ( % d \n, i ) ; 47 else 48 p r i n t f ( %d %d \n, i, r ) ; 49 50 return EXIT SUCCESS ; 51 } 10
3.2 3.2.1 3 3 4 3.2.2 List 2-4(p.44-45) 4 4 11
4: 12
3.2.3 4 List 2-4(p.44-45) 4: 1 #include <s t d i o. h> 2 #include <s t d l i b. h> 3 #include <time. h> 4 5 #define NOT FOUND ( 1) 6 #define N ( 1 0 ) 7 8 int b i n a r y s e a r c h ( int x, int a, int l e f t, int r i g h t ) 9 { 10 int mid ; 11 12 while ( l e f t <r i g h t ) 13 { 14 mid=( l e f t+r i g h t ) / 2 ; 15 i f ( a [ mid]<x ) 16 l e f t=mid+1; 17 else 18 r i g h t=mid ; 19 } 20 i f ( a [ l e f t ]==x ) 21 return l e f t ; 22 23 / / 24 return NOT FOUND; 25 } 26 27 int main ( void ) 28 { 29 int i, r, array [N ] ; 30 31 srand ( ( unsigned int ) time (NULL) ) ; 32 33 / / 34 p r i n t f ( array ) ; 35 p r i n t f ( [ 0 ] : % d, array [0]= rand ( ) %3); 36 for ( i =1; i <N; i ++) 37 p r i n t f ( [%d ]:% d, i, array [ i ]= array [ i 1]+rand ()%3); 38 39 p r i n t f ( \ n : ) ; 40 s c a n f ( %d,& i ) ; 41 42 r=b i n a r y s e a r c h ( i, array, 0,N 1); 43 44 i f ( r==not FOUND) 45 p r i n t f ( % d \n, i ) ; 46 else 47 p r i n t f ( %d %d \n, i, r ) ; 48 49 return EXIT SUCCESS ; 50 } 13
4 4.1 4.1.1 752 778 608 239 956 244 535 840 629 353 [ 1] 1 535 [ 2] 1 643 [ 3] 2 535 [ 4] 2 643 4.1.2 239 244 353 535 608 629 752 752 752 956 [ 1] 3 650 [ 2] 3 752 [ 3] 4 650 [ 4] 4 752 4.2 11 21 ( ) AM 10:40 A4 1 2E 2 14
[1].. ( ), 2004. 15