题目:
每次只要确定以当前长方形的高为高为高时,确定它左边界和右边界,可以利用并查集中的路径压缩做,确定左右边界后,枚举判断最大
代码:
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#define MAX 100100
using namespace std;
int a[MAX];
long long lef[MAX];
long long rig[MAX];
int main ( )
{
int n;
while ( scanf ( "%d" , &n ) , n )
{
for ( int i = 1 ; i <= n ; i++ )
{
scanf ( "%d" , &a[i] );
lef[i] = rig[i] = i;
}
for ( int i = 2 ; i <= n ; i++ )
while ( lef[i] > 1 && a[lef[i]-1] >= a[i] )
lef[i] = lef[lef[i]-1];
for ( int i = n-1 ; i > 0 ; i-- )
while ( rig[i] < n && a[rig[i]+1] >= a[i] )
rig[i] = rig[rig[i]+1];
long long ans = 0;
for ( int i = 1 ; i <= n ; i++ )
ans = max ( ans , ( rig[i] - lef[i] + 1 )* (1LL*a[i]) );
printf ( "%I64d\n" , ans );
}
}