PKU 2082 Terrible Sets(单调栈)

题目大意：原题链接

一排紧密相连的矩形,求能构成的最大矩形面积。

为了防止栈为空,所以提前加入元素(0,0).

#include<cstdio>
#include<stack>
#define maxn 50005
using namespace std; 
struct Element
{
    int length;
    int height;
    Element(){}
    Element(int _w,int _h){
        length=_w,height=_h;
    }
}e[maxn];
int n,curlength,curheight,curArea,maxArea;
stack<Element> S;
int get_Max()
{
    S.push(Element(0,0));
    maxArea=0;
    for(int i=0;i<=n;i++){
        curheight=e[i].height;
        curlength=0;
        while(S.top().height>curheight){
            Element now=S.top();
            S.pop();
            curlength+=now.length;
            curArea=curlength*now.height;
            if(curArea>maxArea)
                maxArea=curArea;
        }
        curlength+=e[i].length;
        S.push(Element(curlength,curheight));
    }
    return maxArea;
}
int main()
{
    while(scanf("%d",&n),n!=-1){
        for(int i=0;i<n;i++)
            scanf("%d%d",&e[i].length,&e[i].height);
        e[n].height=e[n].length=0;
        int ans=get_Max();
        printf("%d\n",ans);
    }
    return 0;
}