RMQ自用模板

#include<bits/stdc++.h>
using namespace std;

const int N=1e5+10;

const int inf=0x7f7f7f7f;

int n,m,max_a[N][31];
int a[N],min_a[N][31];

void build()
{
	for(int i=1;i<=n;i++)
	{
		max_a[i][0]=a[i];
		min_a[i][0]=a[i];
	}
	for(int j=1;(1<<j)<=n;j++)
	{
		for(int i=1;i+(1<<j)-1<=n;i++)
		{
			
			max_a[i][j]=max(max_a[i][j-1],max_a[i+(1<<(j-1))][j-1]);
			min_a[i][j]=min(min_a[i][j-1],min_a[i+(1<<(j-1))][j-1]);
			
		}
	}
}

int minn(int l,int r)
{
	int k=0;
	while((1<<(k+1))<=r-l+1)
	k++;
	return min(min_a[l][k],min_a[r-(1<<k)+1][k]);
	
}

int maxx(int l,int r)
{
	int k=0;
	while((1<<(k+1))<=r-l+1)
	k++;
	return max(max_a[l][k],max_a[r-(1<<k)+1][k]);
}

int main()
{
	ios::sync_with_stdio(0);
	
	cin>>n>>m;
	
	for(int i=1;i<=n;i++)
	cin>>a[i];
	
	build();
	
	while(m--)
	{
		int x,y;
		cin>>x>>y;
		cout<<maxx(x,y)-minn(x,y)<<endl;
	}
}

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