java codility training Genomic-range-query

Question

The task is:

A non-empty zero-indexed string S is given. String S consists of N characters from the set of upper-case English letters A, C, G, T.

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Answer 1

/* 100/100 solution C++. Using prefix sums. Firstly converting chars to integer in nuc variable. Then in a bi-dimensional vector we account the occurrence in S of each nucleoside x in it's respective prefix_sum[s][x]. After we just have to find out the lower nucluoside that occurred in each interval K.

*/ . vector solution(string &S, vector &P, vector &Q) {

int n=S.size();
int m=P.size();
vector > prefix_sum(n+1,vector(4,0));
int nuc;

//prefix occurrence sum
for (int s=0;s=0;u--) {
        if (prefix_sum[Q[k]+1][u] - prefix_sum[P[k]][u] != 0)
            lower_impact_factor = u+1;
    }
    P[k]=lower_impact_factor;
}

return P;

}