text: Update min and max index with the current index and check if it 's a  valid permutation
code: max_ind = max ( max_ind , index_of [ i ] ) NEW_LINE min_ind = min ( min_ind , index_of [ i ] ) NEW_LINE if ( max_ind - min_ind + 1 == i ) : NEW_LINE INDENT cnt += 1 NEW_LINE DEDENT return cnt NEW_LINE