LargestRectangleArea

public class Solution {

public int largestRectangleArea ( int [] height ) {

int len = height . length ;

Stack < Integer > s = new Stack < Integer >();

int maxArea = 0 ;

for ( int i = 0 ; i <= len ; i ++){

int h = ( i == len ? 0 : height [ i ]);

if ( s . isEmpty () || h >= height [ s . peek ()]){

s . push ( i );

} else {

int tp = s . pop ();

maxArea = Math . max ( maxArea , height [ tp ] * ( s . isEmpty () ? i : i - 1 - s . peek ()));

i --;

}

}

return maxArea ;

}

}