RMQ st算法 区间最值模板

#include<bits/stdc++.h>

const int N=1e6+;
const int Logn=;

int f[N][Logn],a[N],lg[N],n,m;

int main(){
    cin>>n>>m;
    rep(i,,n) cin>>a[i];
    lg[]=-;
    rep(i,,n) fa[i][]=a[i],lg[i]=lg[i>>]+;

    rep(j,,Logn)
    for(int i=;i+(<<j)-<=n;i++)
    f[i][j]=max(f[i][j-],f[i+(<<j-)][j-]);

    while(m--){
        int x,y;cin>>x>>y;
        int k=lg[y-x+];
        printf("%d\n",max(f[x][k],f[y-(<<k)+][k]));}
    return ;
}