神奇的超时了最后3个点
```cpp
// luogu-judger-enable-o2
#include<bits/stdc++.h>
using namespace std;
const int logn=21;
const int maxn=2000001;
long long a[maxn],f[maxn][logn],Log[maxn];
inline int read()
{
char c=getchar();int x=0,f=1;
while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
return x*f;
}
int main()
{
int n=read(),m=read();
for (int i=1;i<=m;i++)
f[i][0]=read();
Log[1]=0;
for (int i=2;i<=n;i++)
Log[i]=Log[i>>1]+1;
for (int j=1;j<=logn;j++)
for (int i=1;i+(1<<j)-1<=n;i++)
f[i][j]=max(f[i][j-1],f[i+(1<<(j-1))][j-1]);
for (int i=1;i<=m;i++)
{
int x=read(),y=read();
int s=Log[y-x+1];
printf("%d\n",max(f[x][s],f[y-(1<<s)+1][s]));
}
return 0;
}
```
by lamboo @ 2018-07-24 18:02:12