Largest rectangle area in data histogram

gistfile1.txt

class Solution {
	public int largestRectangleArea(int[] heights) {
		Stack<Integer> s = new Stack<>();
		int result = 0;

		for (int i = 0; i <= heights.length; ) {
			final int value = i < heights.length ? heights[i] : 0;

			if (s.isEmpty() || value > heights[s.peek()]) {
				s.push(i++);
			} else {
				int tmp = s.pop();
				result = Math.max(result,
				                  heights[tmp] * (s.isEmpty() ? i : i - s.peek() - 1));
			}
		}

		return result;
	}
}