<p>You are given an array <code>nums</code> consisting of positive integers.</p>

<p>We call two integers <code>x</code> and <code>y</code> in this problem <strong>almost equal</strong> if both integers can become equal after performing the following operation <strong>at most once</strong>:</p>

<ul>
	<li>Choose <strong>either</strong> <code>x</code> or <code>y</code> and swap any two digits within the chosen number.</li>
</ul>

<p>Return the number of indices <code>i</code> and <code>j</code> in <code>nums</code> where <code>i &lt; j</code> such that <code>nums[i]</code> and <code>nums[j]</code> are <strong>almost equal</strong>.</p>

<p><strong>Note</strong> that it is allowed for an integer to have leading zeros after performing an operation.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">nums = [3,12,30,17,21]</span></p>

<p><strong>Output:</strong> <span class="example-io">2</span></p>

<p><strong>Explanation:</strong></p>

<p>The almost equal pairs of elements are:</p>

<ul>
	<li>3 and 30. By swapping 3 and 0 in 30, you get 3.</li>
	<li>12 and 21. By swapping 1 and 2 in 12, you get 21.</li>
</ul>
</div>

<p><strong class="example">Example 2:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">nums = [1,1,1,1,1]</span></p>

<p><strong>Output:</strong> <span class="example-io">10</span></p>

<p><strong>Explanation:</strong></p>

<p>Every two elements in the array are almost equal.</p>
</div>

<p><strong class="example">Example 3:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">nums = [123,231]</span></p>

<p><strong>Output:</strong> <span class="example-io">0</span></p>

<p><strong>Explanation:</strong></p>

<p>We cannot swap any two digits of 123 or 231 to reach the other.</p>
</div>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>2 &lt;= nums.length &lt;= 100</code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>6</sup></code></li>
</ul>

class Solution:
    def countPairs(self, nums: List[int]) -> int:
        n = len(nums)
        str_nums = []
        result = 0
        for num in nums:
            str_nums.append(str(num))
        for i in range(n):
            for j in range(i+1,n):
                i_num = str_nums[i]
                j_num = str_nums[j]
                if i_num == j_num:
                    # print(i_num, j_num)
                    # print("valide the same")
                    result += 1
                    continue
                len_diff = abs(len(i_num) - len(j_num)) 
                # 751, 50701
                # if len_diff > 2:
                #     continue
                
                tolerance = 2
                diff = []
                if len(i_num) > len(j_num):
                    j_num = "0"*len_diff + j_num
                elif len(i_num) < len(j_num):
                    i_num = "0"*len_diff + i_num
                
                for idx in range(len(i_num)):
                    if i_num[idx] != j_num[idx]:
                        tolerance -= 1
                        diff.append((i_num[idx], j_num[idx]))
                    if tolerance < 0:
                        break
                # print(i_num, j_num, diff, tolerance)
                if tolerance == 0 and diff[0][0] == diff[1][1] and diff[0][1] == diff[1][0]:
                    # print("valid")
                    result += 1
                    
        return result
16400