809. Expressive Words.cpp

class Solution {
public:
    //https://leetcode.com/problems/expressive-words/discuss/122660/C%2B%2BJavaPython-2-Pointers-and-4-pointers
    int expressiveWords(string S, vector<string>& words) {
        int res = 0;
        for (auto &W : words) if (check(S, W)) res++;
        return res;
    }
​
    bool check1(string S, string W) {
        int n = S.size(), m = W.size(), j = 0;
        for (int i = 0; i < n; i++)
            if (j < m && S[i] == W[j]) j++;
            else if (i > 1 && S[i - 2] == S[i - 1] && S[i - 1] == S[i]);
            else if (0 < i && i < n - 1 && S[i - 1] == S[i] && S[i] == S[i + 1]);
            else return false;
        return j == m;
    }
    bool check(string S, string W) {
        int n = S.size(), m = W.size(), i = 0, j = 0;
        for (int i2 = 0, j2 = 0; i < n && j < m; i = i2, j = j2) {
            if (S[i] != W[j]) return false;
            while (i2 < n && S[i2] == S[i]) i2++;
            while (j2 < m && W[j2] == W[j]) j2++;
            if (i2 - i != j2 - j && i2 - i < max(3, j2 - j)) return false;
        }
        return i == n && j == m;
    }
};