add: 220219-CN [golang]

golang/2202/220219-CN.go

@@ -0,0 +1,32 @@
+package main
+
+import "fmt"
+
+// Interval [L, R]
+func reverse(arr *[]int, L, R int) {
+	for L < R {
+		(*arr)[L], (*arr)[R] = (*arr)[R], (*arr)[L]
+		L++
+		R--
+	}
+}
+
+func pancakeSort(arr []int) (ret []int) {
+	n := len(arr)
+	for i := n; i > 0; i-- {
+		maxVal, maxPos := -1, -1
+		for j := 0; j < i; j++ {
+			if arr[j] > maxVal {
+				maxVal, maxPos = arr[j], j
+			}
+		}
+		ret = append(ret, maxPos+1, i)
+		reverse(&arr, 0, maxPos)
+		reverse(&arr, 0, i-1)
+	}
+	return
+}
+
+func main() {
+	fmt.Println(pancakeSort([]int{3, 2, 4, 1}))
+}