int minimumCycleSection(vector<int> &a) {
        size_t len = a.size();
        if(len <= 1) return len;
        int pattern[len];
        memset(pattern, 0, len * 4);
        pattern[0] = -1;
        for(size_t i = 1; i < len; i++){
            int j = pattern[i-1]+1;
            while(a[i] != a[j] && j > 0){
                j = pattern[j-1] + 1;
            }
            pattern[i] = a[i] == a[j] ? j : -1;
        }
        return len - pattern[len-1] - 1;
    }