11572 Unique snowflakes

代码:

#include<cstdio>

#include<set>

#include<algorithm>

usingnamespace std;

 

constint maxn = 1000000 + 5;

intA[maxn];

 

intmain()

{

    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;

}

set中的查找很快。