G

题意：给你一组值，然后询问某个区间的最大值和最小值得差

分析：因为没有更新，所以只需要查找即可，节点保存一个最大值最小值就行了

******************************************************************

#include<stdio.h>
#include<math.h>
#include<string.h>
#include<algorithm>
using namespace std;
#define Lson root<<1,L,tree[root].Mid()
#define Rson root<<1|1,tree[root].Mid()+1,R

const int maxn = 50005;
const int oo = 0xfffffff;

struct Tree
{
    int L, R, MaxH, MinH;
    int Mid(){return (L+R)/2;}
}tree[maxn*4];
int High[maxn], Max, Min;

void Build(int root, int L, int R)
{
    tree[root].L = L, tree[root].R = R;

    if(L == R)
    {
        tree[root].MaxH = tree[root].MinH = High[L];
        return ;
    }

    Build(Lson);
    Build(Rson);

    tree[root].MaxH = max(tree[root<<1].MaxH, tree[root<<1|1].MaxH);
    tree[root].MinH = min(tree[root<<1].MinH, tree[root<<1|1].MinH);
}
void Query(int root, int L, int R)
{
    if(tree[root].L == L && tree[root].R == R)
    {
        Max = max(tree[root].MaxH, Max);
        Min = min(tree[root].MinH, Min);

        return ;
    }

    if(R <= tree[root].Mid())
        Query(root<<1, L, R);
    else if(L > tree[root].Mid())
        Query(root<<1|1, L, R);
    else
    {
        Query(Lson);
        Query(Rson);
    }
}

int main()
{
    int N, M;

    while(scanf("%d%d", &N, &M) != EOF)
    {
        int i, l, r;

        for(i=1; i<=N; i++)
            scanf("%d", &High[i]);
        Build(1, 1, N);

        while(M--)
        {
            Max = -oo, Min = oo;
            scanf("%d%d", &l, &r);
            Query(1, l, r);

            printf("%d
", Max-Min);
        }
    }

    return 0; 

}