Smallest Value of the Rearranged Number
<p>You are given an integer <code>num.</code> <strong>Rearrange</strong> the digits of <code>num</code> such that its value is <strong>minimized</strong> and it does not contain <strong>any</strong> leading zeros.</p>

<p>Return <em>the rearranged number with minimal value</em>.</p>

<p>Note that the sign of the number does not change after rearranging the digits.</p>

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

<pre>
<strong>Input:</strong> num = 310
<strong>Output:</strong> 103
<strong>Explanation:</strong> The possible arrangements for the digits of 310 are 013, 031, 103, 130, 301, 310. 
The arrangement with the smallest value that does not contain any leading zeros is 103.
</pre>

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

<pre>
<strong>Input:</strong> num = -7605
<strong>Output:</strong> -7650
<strong>Explanation:</strong> Some possible arrangements for the digits of -7605 are -7650, -6705, -5076, -0567.
The arrangement with the smallest value that does not contain any leading zeros is -7650.
</pre>

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

<ul>
	<li><code>-10<sup>15</sup> &lt;= num &lt;= 10<sup>15</sup></code></li>
</ul>
Math; Sorting
/**
 * @param {number} num
 * @return {number}
 */
var smallestNumber = function (num) {
    const neg = num < 0;
    num = Math.abs(num);
    const cnt = Array(10).fill(0);

    while (num > 0) {
        cnt[num % 10]++;
        num = Math.floor(num / 10);
    }

    let ans = 0;
    if (neg) {
        for (let i = 9; i >= 0; i--) {
            while (cnt[i] > 0) {
                ans = ans * 10 + i;
                cnt[i]--;
            }
        }
        return -ans;
    }

    if (cnt[0] > 0) {
        for (let i = 1; i < 10; i++) {
            if (cnt[i] > 0) {
                cnt[i]--;
                ans = i;
                break;
            }
        }
    }

    for (let i = 0; i < 10; i++) {
        while (cnt[i] > 0) {
            ans = ans * 10 + i;
            cnt[i]--;
        }
    }

    return ans;
};
