// 2bun-ki
 
#include <stdio.h>
#include <stdlib.h>
 
#define height 4
#define MAX (1<<height)  //ビットシフト演算 2^height と同じ
 
int t[MAX+1]; //配列外アクセス防止のためのダミーで＋１
int sz = 0;
 
 
void initTree(int n){
    int i;
    for(i=0;i<MAX;i++){
        t[i] = -1;
    }
}
 
void printA(){
    int i;
    for(i=1;i<MAX;i++) printf("%d ",t[i]);
    printf("\n");
}
 
int goP(int i){
    if(i/2 == 0) return 0;
    else return i/2;
}
 
int goL(int i){
    if(2*i >= MAX) return 0;
    else return 2*i;
}
 
int goR(int i){
    if(2*i+1 >= MAX) return 0;
    else return 2*i+1;
}
 
void insBT(int x){
    int k,i = 1;
    for(k=0;k<height;k++){
        if(t[i]==-1){
            t[i] = x;
            sz++;
            return;
        }
        if(x < t[i]) i = goL(i);
        else i = goR(i);
    }
    printf("Error : too high -> %d\n",x);
}
 
int searchBT(int x){
	//ここを書く
	int k,i=1;
	for(k=0; k<height; k++){
	 if(t[i]==x){
	   return i;
	 }
	 if(x < t[i]) i = goL(i);
        else i = goR(i);
	}
 
	return -1;
}
 
int main(void){
   int i,x,y,n;
    scanf("%d %d",&n,&x);
    initTree(n);
    for(i=0;i<n;i++){
        scanf("%d",&y);
        insBT(y);
    }
    i = searchBT(x);
    if(i==-1) printf("x is not found\n");
    else printf("t[%d] = %d\n",i,x);
    return 0;
}
 

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