Largest Rectangle in Histogram

Find the largest rectangular area possible in a given histogram where the largest rectangle can be made of a number of contiguous bars. For simplicity, assume that all bars have same width and the width is 1 unit.

For example, consider the following histogram with 7 bars of heights {6, 2, 5, 4, 5, 2, 6}. The largest possible rectangle possible is 12 (see the below figure, the max area rectangle is highlighted in red)

关于本题，还没有刷到，只是在一个视频中提及此问题。思路很巧妙，暂时将解题思路和参考的资料，贴在这里，后期再做完善

参考资料：

http://www.geeksforgeeks.org/largest-rectangle-under-histogram/

http://www.cnblogs.com/felixfang/p/3620086.html

http://www.cnblogs.com/felixfang/p/3676193.html

http://chuansong.me/n/400873436742

http://blog.youkuaiyun.com/yutianzuijin/article/details/52072427