#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=1e5+10;

struct node{LL d,w;};
LL a[N];

int main()
{
    int n;
    while(scanf("%d",&n)!=EOF && n)
    {
        for(int i=1;i<=n;i++)scanf("%lld",&a[i]);
        a[n+1]=0;
        
        LL ans=0;
        stack<node> stk;
        
        for(int i=1;i<=n+1;i++)
        {
            LL w=0;
            while( stk.size() && a[i]<stk.top().d )
            {
                w+=stk.top().w;
                ans=max(ans, stk.top().d  *  w     );
                stk.pop();
            }
            stk.push( node{a[i],w+1} ) ;
        }
        printf("%lld\n",ans);
    }
    return 0;
}

刘志源代码：

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
typedef long long ll;
const int N=1e5+10;
int a[N],l[N],r[N],n;
ll ans;
int main()
{
    a[0]=-1;
    while(scanf("%d",&n),n)
    {
        for(int i=1;i<=n;i++)scanf("%d",&a[i]),l[i]=r[i]=i;
        a[n+1]=ans=-1;
        for(int i=2;i<=n;i++)
            while(a[i]<=a[l[i]-1])l[i]=l[l[i]-1];
        for(int i=n-1;i>=1;i--)
            while(a[i]<=a[r[i]+1])r[i]=r[r[i]+1];
        for(int i=1;i<=n;i++)ans=max(ans,(ll)a[i]*(r[i]-l[i]+1));
        printf("%lld\n",ans);
    }
    return 0;
}