K번째로 큰 요소 찾기

Author: holmir97

FindKthLargestElement.java

@@ -0,0 +1,62 @@
+import java.util.Arrays;
+
+
+// my soluton_USE Arrays
+public class FindKthLargestElement {
+    public static void main(String[] args) {
+        System.out.println(new FindKthLargestElement().findKthLargest(new int[]{5, 2, 4, 3, 1},2));
+    }
+    public int findKthLargest(int[] nums, int k) {
+        Arrays.sort(nums);
+        return nums[nums.length-k];
+    }
+}
+
+/* USE_quickSort
+class Solution {
+    public int findKthLargest(int[] nums, int k) {
+        if (nums == null) {
+            return -1;
+        }
+
+        return quickSelect(nums, 0, nums.length - 1, nums.length - k + 1);
+    }
+
+
+        private int quickSelect(int[] nums, int start, int end, int k) {
+            if (start == end) {
+                return nums[start];
+            }
+
+            int mid = start + (end - start) / 2;
+            int pivot = nums[mid];
+
+            int i = start, j = end;
+            while (i <= j) {
+                while (i <= j && nums[i] < pivot) {
+                    i++;
+                }
+                while (i <= j && nums[j] > pivot) {
+                    j--;
+                }
+                if (i <= j) {
+                    int temp = nums[i];
+                    nums[i] = nums[j];
+                    nums[j] = temp;
+                    i++;
+                    j--;
+                }
+            }
+
+            if (start + k - 1 <= j) {
+                return quickSelect(nums, start, j, k);
+            }
+
+            if (start + k - 1 >= i) {
+                return quickSelect(nums, i, end, k-(i-start));
+            }
+
+            return nums[j+1];
+        }
+}
+ */