#include<stdio.h>
const int Max=1e6+10;
int N,M,ans[Max];
void er(int q){
	int begin=1,end=N,mid;
	while(begin<=end){
		 mid=begin+(end-begin)/2;
		if(ans[mid]==q) break;
	 else if(ans[mid]>q) end=mid-1;
		else begin=mid+1;
	}
	while(ans[mid-1]==q) mid--;
    if(ans[mid]==q) printf("%d ",mid);
    else printf("-1 ");
	return ;
}
int main(){
	scanf("%d %d",&N,&M);
	for(int i=1;i<=N;i++) scanf("%d",&ans[i]);
	for(int i=1;i<=M;i++){
		int n;
		scanf("%d",&n);
		er(n);
	}
	return 0;
}

求助，#1wa，#6tle，其它ac