Create 969-pancake-sorting.js

Author: everthis

969-pancake-sorting.js

@@ -0,0 +1,41 @@
+/**
+ * @param {number[]} arr
+ * @return {number[]}
+ */
+ const pancakeSort = function (arr) {
+  const res = []
+  let n = arr.length
+  while(n) {
+    const idx = indexOf(0, n - 1, n)
+    if(idx === n - 1) {
+      n--
+    } else {
+      flip(0, idx)
+      flip(0, n - 1)
+      res.push(idx + 1, n)
+      n--
+    }
+  }
+  return res
+
+  function flip(l, r) {
+    while(l < r) {
+      const tmp = arr[l]
+      arr[l] = arr[r]
+      arr[r] = tmp
+      l++
+      r--
+    }
+  }
+
+  function indexOf(start, end, target) {
+    let res = -1
+    for(let i = start; i <= end; i++) {
+      if(arr[i]===target) {
+        res = i
+        break
+      }
+    }
+    return res
+  }
+}