#include <stdio.h>
#include <stdlib.h>
int binary_search(const int a[], int n, int x)
{
	int pl=0;
	int pr=n-1;
 
	do
	{
		int pc=(pl+pr)/2;
		if(a[pc]==x)
		return pc;
		else if (a[pc]<x)
		pl=pc+1;
		else
		pr=pc-1;
	}while(pl<=pr);
 
	return -1;
}
int main(void) {
	int n,x,i;
	int *a;
	int ans = -1;
	scanf("%d %d",&n,&x);
	a = (int*)malloc(sizeof(int)*n);
	if(a==NULL){
		printf("ERROR\n");
		return -1;
	}
	for(i=0;i<n;i++){
		scanf("%d",&a[i]);
	}
	ans = binary_search(a,n,x);
	if(ans != -1) printf("a[%d] = %d\n",ans,a[ans]);
	else printf("not found\n");
	free(a);
	return 0;
}
 

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