2019.9.5 Balanced Lineup

题目传送门

板子*3

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#define int long long
using namespace std;
int n,q,h[500050],dp1[500050][65],dp2[500050][65];
void init()
{
    for(int i=1;i<=n;i++)dp1[i][0]=h[i];
    for(int j=1;(1<<j)<=n;j++)
        for(int i=1;i+(1<<j)-1<=n;i++)
            dp1[i][j]=max(dp1[i][j-1],dp1[i+(1<<j-1)][j-1]);
    for(int i=1;i<=n;i++)dp2[i][0]=h[i];
    for(int j=1;(1<<j)<=n;j++)
        for(int i=1;i+(1<<j)-1<=n;i++)
            dp2[i][j]=min(dp2[i][j-1],dp2[i+(1<<j-1)][j-1]);
}
int maxnum(int l,int r)
{
    int k=log2(r-l+1);
    return max(dp1[l][k],dp1[r-(1<<k)+1][k]);
}
int minnum(int l,int r)
{
    int k=log2(r-l+1);
    return min(dp2[l][k],dp2[r-(1<<k)+1][k]);
}
signed main()
{
    scanf("%lld%lld",&n,&q);
    for(int i=1;i<=n;i++)scanf("%lld",&h[i]);
    init();
    int x,y;
    for(int i=1;i<=q;i++)
    {
        scanf("%lld%lld",&x,&y);
        printf("%lld\n",maxnum(x,y)-minnum(x,y));
    }
    return 0;
}