Create 1095-find-in-mountain-array.kt

Author: a93a

kotlin/1095-find-in-mountain-array.kt

@@ -0,0 +1,50 @@
+class Solution {
+    fun findInMountainArray(target: Int, mountainArr: MountainArray): Int {
+        var l = 1
+        var r = mountainArr.length() - 2
+        var peak = -1
+        while (l <= r) {
+            val m = (l + r) / 2
+            val left = mountainArr.get(m - 1)
+            val mid = mountainArr.get(m)
+            val right = mountainArr.get(m + 1)
+
+            if (left < mid && mid < right) {
+                l = m + 1
+            } else if (left > mid && mid > right) {
+                r = m - 1
+            } else {
+                peak = m
+                break
+            }
+        }
+
+        l = 0
+        r = peak
+        while (l <= r) {
+            val m = (l + r) / 2
+            val value = mountainArr.get(m)
+            if (value < target)
+                l = m + 1
+            else if (value > target)
+                r = m - 1
+            else
+                return m
+        }
+
+        l = peak
+        r = mountainArr.length() - 1
+        while (l <= r) {
+            val m = (l + r) / 2
+            val value = mountainArr.get(m)
+            if (value < target)
+                r = m - 1
+            else if (value > target)
+                l = m + 1
+            else
+                return m
+        }
+
+        return -1
+    }
+}