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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. int binary_search(int a[],int n,int x){
  5. 	int lef,mid,rig;
  6. 	lef=0;rig=n-1;
  7. 	mid=(lef+rig)/2;
  8. 	while(1){
  9. 		printf("%d=mid%d=lef%d=rig\n",mid,lef,rig);
  10. 		if(a[mid] == x){
  11. 			return mid;
  12. 		}
  13. 		else if(a[mid]<x){
  14.  
  15. 			lef = mid+1;
  16. 			mid=(lef+rig)/2;
  17. 		}
  18. 		else if(a[mid]>x){
  19. 			rig = mid-1;
  20. 			mid=(lef+rig)/2;
  21. 		}
  22. 		if(lef>rig)return -1;
  23. 	}
  24.  
  25.  
  26.  
  27. }
  28.  
  29. int main(void) {
  30. 	int n,x,i;
  31. 	int *a;
  32. 	int ans = -1;
  33. 	scanf("%d %d",&n,&x);
  34. 	a = (int*)malloc(sizeof(int)*n);
  35. 	if(a==NULL){
  36. 		printf("ERROR\n");
  37. 		return -1;
  38. 	}
  39. 	for(i=0;i<n;i++){
  40. 		scanf("%d",&a[i]);
  41. 	}
  42. 	ans = binary_search(a,n,x);
  43. 	if(ans != -1) printf("a[%d] = %d\n",ans,a[ans]);
  44. 	else printf("not found\n");
  45. 	free(a);
  46. 	return 0;
  47. }
  48.  
Success #stdin #stdout 0s 5308KB
comments (?)
stdin
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22 6666
1 2 3 4 5 8 9 13 16 21 25 27 31 33 44 45 52 62 214 626 4325 6666
stdout
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10=mid0=lef21=rig
16=mid11=lef21=rig
19=mid17=lef21=rig
20=mid20=lef21=rig
21=mid21=lef21=rig
a[21] = 6666
https://ideone.com/9lskqv
language:
C (gcc 8.3)
created:
11 days ago
visibility:
public

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