Kotlin: 84. Largest Rectangle in Histogram

Author: MaratKhakim

kotlin/84-Largest-Rectangle-In-Histogram.kt

@@ -0,0 +1,27 @@
+class Solution {
+    fun largestRectangleArea(heights: IntArray): Int {
+        val st = LinkedList<IntArray>()
+        st.push(intArrayOf(-1, 0))
+        var max = 0
+
+        for (i in heights.indices) {
+            var start = i
+
+            while (!st.isEmpty() && st.peek()[1] > heights[i]) {
+                val curr = st.pop()
+                val height = curr[1]
+                start = curr[0]
+                max = Math.max(max, height * (i - start))
+            }
+
+            st.push(intArrayOf(start, heights[i]))
+        }
+
+        while (!st.isEmpty()) {
+            val curr = st.pop()
+            max = Math.max(max, curr[1] * (heights.size - curr[0]))
+        }
+
+        return max
+    }
+}