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class Solution {
public:
    bool isLowercaseVowel(int c){
        return (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u');
    }
    vector<int> vowelStrings(vector<string>& words, vector<vector<int>>& queries) {
        int n = words.size();
        vector < int > cumulative(n+1, 0);
        vector < int > ans(queries.size(),0);

        for(int i=0;i<n;i++) {
            int m = words[i].size();
            int prev = max(i, 0);
            if(isLowercaseVowel(words[i][0]) && isLowercaseVowel(words[i][m-1])) {     
                cumulative[i+1] = cumulative[prev] + 1;
            } else {
                cumulative[i+1] = cumulative[prev];
            }
        }
        for(int i=0;i<queries.size();i++) {
            int l = queries[i][0] , r = queries[i][1];

            ans[i] = (cumulative[r+1] - cumulative[l]);
        }

        return ans;
    }
};