RMQ区间最值问题
因为之前学过树上倍增，还是挺好理解的，不能处理动态的
#include<cstdio>
#include<cstring>
#include<algorithm>
#define M 25
#define N 100005
using namespace std;
int n,m;
int a[N],Log[N];
int f[N][M];
void GetLog()
{
int i;
Log[1]=0;
for(i=2;i<=n+1;++i)
Log[i]=Log[i/2]+1;
}
void RMQ()
{
int i,j;
for(i=1;i<=n;++i)
f[i][0]=a[i];
for(j=1;(1<<j)<=n;++j)
for(i=1;i+(1<<(j-1))<=n;++i)
f[i][j]=max(f[i][j-1],f[i+(1<<(j-1))][j-1]);
}
int main()
{
int l,r,i,k,ans;
scanf("%d%d",&n,&m);
for(i=1;i<=n;++i)
scanf("%d",&a[i]);
GetLog();
RMQ();
for(i=1;i<=m;++i)
{
scanf("%d%d",&l,&r);
k=Log[r-l+1];
ans=max(f[l][k],f[r-(1<<k)+1][k]);
printf("%d\n",ans);
}
return 0;
}
