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=0,rig=n-1,mid;
  9. 	while(lef<=rig){
  10. 		mid = (lef+rig)/2;
  11. 		if(a[mid]==x){
  12. 			return mid;
  13. 		}
  14. 		else if(a[mid]>=x){
  15. 			rig = mid-1;
  16. 		}
  17. 		else if(a[mid]<x){
  18. 			lef = mid+1;
  19. 		}
  20. 	}	
  21. 	if(lef>rig) {
  22. 		return -1;
  23. 	}
  24. }
  25.  
  26. int main(void) {
  27. 	int n,x,i;
  28. 	int *a;
  29. 	int ans = -1;
  30. 	scanf("%d %d",&n,&x);
  31. 	a = (int*)malloc(sizeof(int)*n);
  32. 	if(a==NULL){
  33. 		printf("ERROR\n");
  34. 		return -1;
  35. 	}
  36. 	for(i=0;i<n;i++){
  37. 		scanf("%d",&a[i]);
  38. 	}
  39. 	ans = binary_search(a,n,x);
  40. 	if(ans != -1) printf("a[%d] = %d\n",ans,a[ans]);
  41. 	else printf("not found\n");
  42. 	free(a);
  43. 	return 0;
  44. }
  45.  
Success #stdin #stdout 0.01s 5292KB
comments (?)
stdin
copy 
6
2
1
2
4
6
8
9
stdout
copy 
a[1] = 2
https://ideone.com/dGlvri
language:
C (gcc 8.3)
created:
3 days 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!