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76 lines
1.7 KiB
C
76 lines
1.7 KiB
C
/* Program to demonstrate Randomized quick sort (recursive) */
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#include <stdio.h>
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#include <stdlib.h>
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#include <conio.h>
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void quick(int x[], int lb, int ub) ;
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int partition(int x[], int lb, int ub) ;
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void show(int x[], int lb, int ub) ;
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void main()
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{
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int i, n, x[20] ;
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clrscr() ;
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printf("Enter the number of elements: ") ;
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scanf("%d",&n) ;
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printf("Enter the elements:\n") ;
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for(i=0; i<n; i++)
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scanf("%d",&x[i]) ;
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quick(x,0,n-1) ;
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printf("Sorted array is as shown:\n") ;
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for(i=0; i<n; i++)
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printf("%d ",x[i]) ;
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getch() ;
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}
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void quick(int x[], int lb, int ub)
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{
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int j, k, temp ;
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if(lb<ub)
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{
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k=rand()%(ub-lb+1) + lb ;
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temp=x[k] ;
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x[k]=x[lb] ;
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x[lb]=temp ;
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j=partition(x,lb,ub) ;
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quick(x,lb,j-1) ;
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quick(x,j+1,ub) ;
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}
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}
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int partition(int x[], int lb, int ub)
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{
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int a, down, up, temp ;
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a=x[lb] ;
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up=ub ;
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down=lb ;
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while(down<up)
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{
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while(x[down]<=a&&down<ub)
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down++ ;
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while(x[up]>a)
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up-- ;
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if(down<up)
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{
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temp=x[down] ;
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x[down]=x[up] ;
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x[up]=temp ;
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}
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}
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x[lb]=x[up] ;
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x[up]=a ;
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show(x,lb,ub) ;
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return up ;
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}
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void show(int x[], int lb, int ub)
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{
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int i ;
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for(i=lb ; i<=ub ; i++)
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printf("%d ",x[i]) ;
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printf("\n\n") ;
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}
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/* The method show() is optional. It is written to show output of each pass. It may not be written in theory exam. It is required only in practical exams */
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