#P1443. POJ2559 Largest Rectangle in a Histogram

POJ2559 Largest Rectangle in a Histogram

说明

A histogram is a polygon composed of a sequence of rectangles aligned at a common ba<x>se line. The rectangles have equal widths but may have different heights. For example, the figure on the left shows the histogram that consists of rectangles with the heights 2, 1, 4, 5, 1, 3, 3, measured in units where 1 is the width of the rectangles: 
如下图所示,在一条水平线上方有若干个矩形,求包含与这些矩形的并集内部的最大矩形的面积(在下图中,答案就是阴影部分的面积),矩形个数≤105 

Usually, histograms are used to represent discrete distributions, e.g., the frequencies of characters in texts. Note that the order of the rectangles, i.e., their heights, is important. Calculate the area of the largest rectangle in a histogram that is aligned at the common ba<x>se line, too. The figure on the right shows the largest aligned rectangle for the depicted histogram.

输入格式

The input contains several test cases. Each test case describes a histogram and starts with an integer n, denoting the number of rectangles it is composed of. You may assume that 1<=n<=100000. Then follow n integers h1,...,hn, where 0<=hi<=1000000000. These numbers denote the heights of the rectangles of the histogram in left-to-right order. The width of each rectangle is 1. A zero follows the input for the last test case.

输出格式

For each test case output on a single line the area of the largest rectangle in the specified histogram. Remember that this rectangle must be aligned at the common ba<x>se line.

样例

7 2 1 4 5 1 3 3
4 1000 1000 1000 1000
0
8
4000

提示

Huge input, scanf is recommended.