I am missing something in the code

#1

My logic is fine but some thing is not correct in my code …not getting exact output

#2

dp[i]=dp[i]-dp[j-1];
this should be
dp[i]=dp[i]-dp[j];

also
m.insert(make_pair(ch,i));
this should be
m[ch]=(i-1);
because you have to maintain the last occurence

also take mod

Modified Code

#3

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