唯一的雪花

Posted 2020-07-23 神犇(shenben)

//唯一的雪花 uva 11572 《紫书》p239-241 
//1
#include<cstdio>
#include<set>
#include<algorithm>
using namespace std;
#define N 1000050
int a[N];
int main(){
    int t,n;
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        for(int i=0;i<n;i++) scanf("%d",a+i);
        set<int>s;
        int l=0,r=0,ans=0;
        while(r<n){
            while(r<n&&!s.count(a[r])) s.insert(a[r++]);
            ans=max(ans,r-l);
            s.erase(a[l++]);  
        }
        printf("%d\n",ans);
    }
    return 0;
} 
//2
#include<cstdio>
#include<map>
using namespace std;
#define N 1000100
int a[N],last[N];
map<int,int>cur;
int main(){
    int t,n;
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        cur.clear();
        for(int i=0;i<n;i++){
            scanf("%d",a+i);
            if(!cur.count(a[i])) last[i]=-1;
            else last[i]=cur[a[i]];
            cur[a[i]]=i;
        }
        int l=0,r=0,ans=0;
        while(r<n){
            while(r<n&&last[r]<l) r++;
            ans=max(ans,r-l);
            l++;
        }
        printf("%d\n",ans);
    }
    
    
    return 0;
}