Largest Rectangle in Histogram

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.

Above is a histogram where width of each bar is 1, given height = [2,1,5,6,2,3].

The largest rectangle is shown in the shaded area, which has area = 10 unit.

For example,
Given height = [2,1,5,6,2,3],
return 10.

class Solution {
public:
     int largestRectangleArea(vector< int> &height) 
    {
         int max= 0;
         int minl[height.size()];
         int minr[height.size()];
         for( int i= 0;i<height.size();i++)
        {
             int index=i- 1;
             while(index>= 0 && height[index]>=height[i]) index=minl[index]- 1;
            minl[i]=index+ 1;
        }
         for( int i=height.size()- 1;i>= 0;i--)
        {
             // right
             int index=i+ 1;
             while(index<height.size() && height[index]>=height[i]) index=minr[index]+ 1;
            minr[i]=index- 1;
        }
         for( int i= 0;i<height.size();i++)
             if((minr[i]-minl[i]+ 1)*height[i]>max) 
                max=(minr[i]-minl[i]+ 1)*height[i];
         return max;
    }
};