Implement maxFrequency method for frequency calculation

src/test/java/LeetCode/Maximum_Frequency_of_an_Element_After_Performing_Operations_I/LC_maxfreqeleafterop1.java

@@ -0,0 +1,64 @@
+import java.util.*;
+class LC_maxfreqeleafterop1 {
+
+    public int maxFrequency(int[] nums, int k, int numOperations) {
+        Arrays.sort(nums);
+
+        int ans = 0;
+        Map<Integer, Integer> numCount = new HashMap<>();
+
+        int lastNumIndex = 0;
+        for (int i = 0; i < nums.length; ++i) {
+            if (nums[i] != nums[lastNumIndex]) {
+                numCount.put(nums[lastNumIndex], i - lastNumIndex);
+                ans = Math.max(ans, i - lastNumIndex);
+                lastNumIndex = i;
+            }
+        }
+
+        numCount.put(nums[lastNumIndex], nums.length - lastNumIndex);
+        ans = Math.max(ans, nums.length - lastNumIndex);
+
+        for (int i = nums[0]; i <= nums[nums.length - 1]; i++) {
+            int l = leftBound(nums, i - k);
+            int r = rightBound(nums, i + k);
+            int tempAns;
+            if (numCount.containsKey(i)) {
+                tempAns = Math.min(r - l + 1, numCount.get(i) + numOperations);
+            } else {
+                tempAns = Math.min(r - l + 1, numOperations);
+            }
+            ans = Math.max(ans, tempAns);
+        }
+
+        return ans;
+    }
+
+    private int leftBound(int[] nums, int value) {
+        int left = 0;
+        int right = nums.length - 1;
+        while (left < right) {
+            int mid = (left + right) / 2;
+            if (nums[mid] < value) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
+        }
+        return left;
+    }
+
+    private int rightBound(int[] nums, int value) {
+        int left = 0;
+        int right = nums.length - 1;
+        while (left < right) {
+            int mid = (left + right + 1) / 2;
+            if (nums[mid] > value) {
+                right = mid - 1;
+            } else {
+                left = mid;
+            }
+        }
+        return left;
+    }
+}