fork download
copy 
  1. //第3回 課題１
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4.  
  5. //この関数を実装する
  6. int binary_search(int a[],int n,int x){
  7. 	//この関数の内側だけを書く
  8. 	int lef,rig,mid,k;
  9. 	lef = 0,rig = n-1,mid = (lef+rig)/2;
  10. 	do{
  11. 		if(a[mid]<x){
  12. 			lef = mid+1;
  13. 			mid = ((lef+rig)/2);
  14.  
  15. 		}
  16. 		else if(a[mid] == x){
  17. 			return mid;
  18. 		}
  19. 		else {
  20. 			rig = mid-1;
  21. 			mid = ((lef+rig)/2);
  22.  
  23. 		}
  24.  
  25. 	}while(lef<=rig);
  26. 		return -1;
  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. }
Success #stdin #stdout 0s 5324KB
comments (?)
stdin
copy 
12 5
1 2 3 4 5 8 9 13 16 21 25 27
stdout
copy 
a[4] = 5
https://ideone.com/o2gtbF
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!