1 <= nums[i] <= 5 * 10^4

Solution

Method 1 – Sort and Count Unique Levels

Intuition

Each time we reduce the largest value to the next largest, we perform an operation for every occurrence of the current largest. The total number of operations is the sum of the counts of all elements above the minimum, weighted by their position in the sorted unique list.

Approach

Sort the array.
For each unique value (from smallest to largest), count how many numbers are greater than it.
For each group, add the number of operations needed (which is the count of numbers before it in the sorted order).
Return the total operations.

Code

[{"language":"C++","code":"class Solution {\npublic:\n    int reductionOperations(vector<int>& nums) {\n        sort(nums.begin(), nums.end());\n        int ans = 0, cnt = 0;\n        for (int i = 1; i < nums.size(); ++i) {\n            if (nums[i] != nums[i-1]) ++cnt;\n            ans += cnt;\n        }\n        return ans;\n    }\n};","lang":"cpp","html":"<pre class=\"shiki shiki-themes github-light github-dark\" style=\"background-color:#fff;--shiki-dark-bg:#24292e;color:#24292e;--shiki-dark:#e1e4e8\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">class</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\"> Solution</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> {</span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">public:</span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">    int</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\"> reductionOperations</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">(</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">vector</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">&#x3C;</span><span style=\"color:#D73A49;--shiki-dark:#F97583\">int</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">></span><span style=\"color:#D73A49;--shiki-dark:#F97583\">&#x26;</span><span style=\"color:#E36209;--shiki-dark:#FFAB70\"> nums</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">) {</span></span>\n<span class=\"line\"><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">        sort</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">(nums.</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">begin</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">(), nums.</span><span style=\"color:#6F42C1;--shiki-dark:#B392F0\">end</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">());</span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">        int</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> ans </span><span style=\"color:#D73A49;--shiki-dark:#F97583\">=</span><span style=\"color:#005CC5;--shiki-dark:#79B8FF\"> 0</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">, cnt </span><span style=\"color:#D73A49;--shiki-dark:#F97583\">=</span><span style=\"color:#005CC5;--shiki-dark:#79B8FF\"> 0</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\">;</span></span>\n<span class=\"line\"><span style=\"color:#D73A49;--shiki-dark:#F97583\">        for</span><span style=\"color:#24292E;--shiki-dark:#E1E4E8\"> (</span><span style=\"color:#D73A49;--shiki-dark

Related Tags