Largest rectangle in histogram

Signed-off-by: begeekmyfriend <[email protected]>

084_largest_rectangle_in_histogram/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test rect_in_histogram.c

084_largest_rectangle_in_histogram/rect_in_histogram.c

@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+static int largestRectangleArea(int* heights, int heightsSize)
+{
+    int i, max_area = 0;
+    for (i = 0; i < heightsSize; i++) {
+        if (i > 0 && heights[i - 1] == heights[i]) {
+            continue;
+        }
+        int low = i;
+        int high = i;
+        while (low - 1 >= 0 && heights[low - 1] >= heights[i]) {
+            low--;
+        }
+        while (high + 1 < heightsSize && heights[high + 1] >= heights[i]) {
+            high++;
+        }
+        int area = (high - low + 1) * heights[i];
+        max_area = area > max_area ? area : max_area;
+    }
+    return max_area;
+}
+
+int main(void)
+{
+    int nums[] = { 2, 1, 5, 6, 2, 3 };
+    int count = sizeof(nums) / sizeof(*nums);
+    printf("%d\n", largestRectangleArea(nums, count));
+    return 0;
+}