<p>You are given a <strong>0-indexed</strong> integer array <code>nums</code> of length <code>n</code>.</p> <p>We want to group the indices so for each index <code>i</code> in the range <code>[0, n - 1]</code>, it is assigned to <strong>exactly one</strong> group.</p> <p>A group<strong> </strong>assignment is <strong>valid</strong> if the following conditions hold:</p> <ul> <li>For every group <code>g</code>, all indices <code>i</code> assigned to group <code>g</code> have the same value in <code>nums</code>.</li> <li>For any two groups <code>g<sub>1</sub></code> and <code>g<sub>2</sub></code>, the <strong>difference</strong> between the <strong>number of indices</strong> assigned to <code>g<sub>1</sub></code> and <code>g<sub>2</sub></code> should <strong>not exceed</strong> <code>1</code>.</li> </ul> <p>Return <em>an integer denoting </em><em>the <strong>minimum</strong> number of groups needed to create a valid group assignment.</em></p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> nums = [3,2,3,2,3] <strong>Output:</strong> 2 <strong>Explanation:</strong> One way the indices can be assigned to 2 groups is as follows, where the values in square brackets are indices: group 1 -> [0,2,4] group 2 -> [1,3] All indices are assigned to one group. In group 1, nums[0] == nums[2] == nums[4], so all indices have the same value. In group 2, nums[1] == nums[3], so all indices have the same value. The number of indices assigned to group 1 is 3, and the number of indices assigned to group 2 is 2. Their difference doesn't exceed 1. It is not possible to use fewer than 2 groups because, in order to use just 1 group, all indices assigned to that group must have the same value. Hence, the answer is 2.</pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> nums = [10,10,10,3,1,1] <strong>Output:</strong> 4 <strong>Explanation:</strong> One way the indices can be assigned to 4 groups is as follows, where the values in square brackets are indices: group 1 -> [0] group 2 -> [1,2] group 3 -> [3] group 4 -> [4,5] The group assignment above satisfies both conditions. It can be shown that it is not possible to create a valid assignment using fewer than 4 groups. Hence, the answer is 4.</pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= nums.length <= 10<sup>5</sup></code></li> <li><code>1 <= nums[i] <= 10<sup>9</sup></code></li> </ul>