Codeforces Round #833 (Div. 2) B. Diverse Substrings

Codeforces Round #833 (Div. 2) B. Diverse Substrings

In a diverse string, there are at most $10$ distinct characters: ‘0’, ‘1’, $\dots$, ‘9’. Therefore, each of these characters can appear at most $10$ times in a diverse string.

With all this in mind, the maximum possible length of a diverse string is $10^2=100$. To solve this problem, we only need to check whether each substring of length $l\le 100$ is diverse.

Time complexity per testcase: $O(n\cdot 10^2)$

#include
using namespace std;

typedef long long LL;

int main()
{
    int T;cin>>T;
    while(T--)
    {
        int n;cin>>n;
        string s;cin>>s;

        int res=0;
        for(int i=0;i<n;i++)
        {
            vector<int> d(10);
            int mx=0,len=0;
            for(int j=i;j<min(i+100,n);j++)
            {
                if(d[s[j]-'0']==0) len++;
                d[s[j]-'0']++;
                mx=max(mx,d[s[j]-'0']);

                if(mx<=len) res++;
            }
        }
        cout<<res<<endl;
    }
    return 0;
}
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