poj 3264

最近OI颓废了。。。文化课也貌似要颓废了QAQ两者有点难调节啊。。。

先刷个水题。。。初看就想用线段树或BIT，其实可以用RMQ那。。。于是代码短了点

#include<cstdio>
#include<queue>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#define inc(i,l,r) for(i=l;i<=r;i++)
#define dec(i,l,r) for(i=l;i>=r;i--)
#define inf 1e9
#define mem(a) memset(a,0,sizeof(a))
#define ll long long
#define succ(x) (1<<x)
#define NM 50000+5
using namespace std;
int read(){
    int x=0,f=1;char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}
    while(isdigit(ch))x=x*10+ch-'0',ch=getchar();
    return x*f;
}
int n,m,x,y,k,i,j,f[NM][25],d[NM][25],p=20;
int main(){
    n=read();m=read();
    inc(i,1,n)d[i][0]=f[i][0]=read();
    inc(j,1,p)
    inc(i,1,n){
        f[i][j]=f[i][j-1];d[i][j]=d[i][j-1];
        if(i+succ(j-1)<=n){
        f[i][j]=max(f[i][j],f[i+succ(j-1)][j-1]);
        d[i][j]=min(d[i][j],d[i+succ(j-1)][j-1]);
        }
    }
    inc(i,1,m){
        x=read();y=read();
        k=log(y-x+1.0)/log(2.0);
        printf("%d
",max(f[x][k],f[y-succ(k)+1][k])-min(d[x][k],d[y-succ(k)+1][k]));
    }
    return 0;
}