1279 扔盘子

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
const int MAXN = 5e4 + 10;
const int INF = 0x3f3f3f3f;
int width[MAXN];
int m, n;
int main(){
	scanf("%d%d", &n, &m);
	fill(width, width + MAXN, INF);
	for(int i = 1; i <= n; ++i){
		scanf("%d", &width[i]);
		width[i] = min(width[i], width[i - 1]);
	}
	int ans = 0, flag = n, plate;
	for(int i = 0; i < m; ++i){
		scanf("%d", &plate);
		for(; flag >= 1; --flag){
			if(width[flag] >= plate){
				flag--;
				ans++;
				break;
			}
		}
	} 
	printf("%d\n", ans);
	return 0;
}