#include <stdio.h>
#include <stdlib.h>
//この関数を実装する
int binary_search(int a[],int n,int x){
int lef=0,rig=n-1,mid=(lef+rig)/2;
while(1){
if(a[mid]==x){
return mid;
break;
}
else if(a[mid]<x){
lef=mid+1;
mid=(lef+rig)/2;
}
else if(a[mid]>x){
rig=mid-1;
mid=(lef+rig)/2;
}
}
}
int main(void) {
int n,x,i;
int *a;
int ans = -1;
a
= (int*)malloc(sizeof(int)*n
); if(a==NULL){
return -1;
}
for(i=0;i<n;i++){
}
ans = binary_search(a,n,x);
if(ans
!= -1) printf("a[%d] = %d\n",ans
,a
[ans
]); return 0;
}
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