这份代码这样写在test6会输出chong

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5; 
template<typename T>inline void read(T &x){
	x=0;int f=1;char c=getchar();
	while(!isdigit(c)){if(c=='-')f=-1;c=getchar();}
	while(isdigit(c)) x=(x<<1)+(x<<3)+(c^48),c=getchar();
	x*=f;
}
int T,n,mxb,s,ans,a[N],idx;
int mp[N<<2];
int t[N],f;
inline void add(int x,int y){
	for(;x<=mxb;x+=x&-x) t[x]=max(t[x],y);
}
inline int query(int x){
	int ans=0;
	for(;x;x-=x&-x) ans=max(ans,t[x]);
	return ans;
}
int main(){
	read(T),read(n),read(mxb),read(s);
	while(T--){
		idx=0;
		for(int i=1;i<=n;++i){
			read(a[i]);
			if(mp[a[i]]){
				cout<<"chong";
				return 0;
			}
		}
		for(int i=1;i<=n;++i){
			if(!mp[a[i]]) ++idx,mp[a[i]]=1;
		}
		if(s>=idx){
			printf("%d\n",idx);
			continue;
		}
		ans=0;
		memset(t,0,sizeof(t));
		for(int j=1;j<=s;++j)
		for(int i=1;i<=n;++i){
			f=query(a[i]-1)+1;
			ans=max(ans,f);
			add(a[i],f);
		}
		printf("%d\n",ans);
		memset(mp,0,sizeof(mp));
	}
    return 0;
}

但是吧memset放前面就A了

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5; 
template<typename T>inline void read(T &x){
	x=0;int f=1;char c=getchar();
	while(!isdigit(c)){if(c=='-')f=-1;c=getchar();}
	while(isdigit(c)) x=(x<<1)+(x<<3)+(c^48),c=getchar();
	x*=f;
}
int T,n,mxb,s,ans,a[N],idx;
int mp[N<<2];
int t[N],f;
inline void add(int x,int y){
	for(;x<=mxb;x+=x&-x) t[x]=max(t[x],y);
}
inline int query(int x){
	int ans=0;
	for(;x;x-=x&-x) ans=max(ans,t[x]);
	return ans;
}
int main(){
	read(T),read(n),read(mxb),read(s);
	while(T--){
		idx=0;
        memset(mp,0,sizeof(mp));    			     
		for(int i=1;i<=n;++i){
			read(a[i]);
			if(mp[a[i]]){
				cout<<"chong";
				return 0;
			}
		}
		for(int i=1;i<=n;++i){
			if(!mp[a[i]]) ++idx,mp[a[i]]=1;
		}
		if(s>=idx){
			printf("%d\n",idx);
			continue;
		}
		ans=0;
		memset(t,0,sizeof(t));
		for(int j=1;j<=s;++j)
		for(int i=1;i<=n;++i){
			f=query(a[i]-1)+1;
			ans=max(ans,f);
			add(a[i],f);
		}
		printf("%d\n",ans);
		
	}
    return 0;
}