把log2预处理一下试试
by gxy001 @ 2020-08-06 09:32:14
这边建议用快读呢亲
by Prean @ 2020-08-06 09:36:16
@[dengyunsheng](/user/340333)
by JK_LOVER @ 2020-08-06 09:36:58
```cpp
#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5,M=18;
int s[N];
int n,m;
int f[N][M];
void init(){
for(int j=0;j<M;j++){
for(int i=1;i+(1<<j)-1<=n;i++){
if(!j) f[i][j]=s[i];
else f[i][j]=max(f[i][j-1],f[i+(1 << j-1)][j-1]);
}
}
}
int query(int l,int r){
int len=r-l+1;
int k=log2(len);
return max(f[l][k],f[r-(1<<k)+1][k]);
}
int main(){
scanf("%d %d",&n,&m);
for(int i=1;i<=n;i++) scanf("%d",&s[i]);
init();
while(m--){
int l,r;
scanf("%d %d",&l,&r);
printf("%d\n",query(l,r));
}
return 0;
}
```
by JK_LOVER @ 2020-08-06 09:37:06
~~~
int k=log2(len);
~~~
亲，有 $\log_2$ 这个函数呢
by JK_LOVER @ 2020-08-06 09:37:46
@[JK_LOVER](/user/227824) 建议
```
#define log2(x) (31-__builtin_clz(x))
```
by 鏡音リン @ 2020-08-06 09:44:28
@[鏡音リン](/user/90893) 谢谢$QWQ$
by JK_LOVER @ 2020-08-06 09:46:07
@[JK_LOVER](/user/227824) log2很慢的
by tommy0221 @ 2020-08-06 10:01:53
@[世外明月](/user/123384) 被大佬看笑话了/kk
by JK_LOVER @ 2020-08-06 10:06:06
我是菜鸡
by tommy0221 @ 2020-08-06 10:12:56