add new solutions

solutions/2/q215/solution.go

@@ -0,0 +1,37 @@
+package q215
+
+func findKthLargest(nums []int, k int) int {
+	// build max-heap
+	for i := 1; i < len(nums); i++ {
+		for j := i; j > 0; j = (j - 1) / 2 {
+			parent := (j - 1) / 2
+			if nums[j] > nums[parent] {
+				nums[j], nums[parent] = nums[parent], nums[j]
+			}
+		}
+	}
+
+	for range k - 1 {
+		// pop the heap
+		nums[0] = nums[len(nums)-1]
+		nums = nums[:len(nums)-1]
+
+		i := 0
+		for i*2+1 < len(nums) {
+			l, r := i*2+1, i*2+2
+			next := l
+			if r < len(nums) && nums[r] > nums[l] {
+				next = r
+			}
+			if nums[i] >= nums[next] {
+				break
+			}
+			nums[i], nums[next] = nums[next], nums[i]
+			i = next
+		}
+	}
+
+	return nums[0]
+}
+
+var _ = findKthLargest