POJ 3264

/*
Balanced Lineup
区间最值的查询
*/
#include<cstdio>
#include<cstring>
#include<vector>
#include<algorithm>
using namespace std;
#define lson (pos<<1)
#define rson (pos<<1|1)
const int maxn = 55555;
int min_v[maxn << 2],max_v[maxn << 2];
void pushup(int pos){
    min_v[pos] = min(min_v[lson],min_v[rson]);
    max_v[pos] = max(max_v[lson],max_v[rson]);
}
void build(int l,int r,int pos){
    if(l == r){
        int v;
        scanf("%d",&v);
        min_v[pos] = max_v[pos] = v;
        return;
    }
    int mid = (l + r) >> 1;
    build(l,mid,lson);
    build(mid + 1,r,rson);
    pushup(pos);
}
void query(int L,int R,int l,int r,int pos,int& min_size,int& max_size){
    if(l <= L && R <= r){
        min_size = min(min_size,min_v[pos]);
        max_size = max(max_size,max_v[pos]);
        return;
    }
    int mid = (L + R) >> 1;
    if(l <= mid)
        query(L,mid,l,r,lson,min_size,max_size);
    if(r > mid)
        query(mid + 1,R,l,r,rson,min_size,max_size);
}
int main(){
    int n,m;
    while(scanf("%d%d",&n,&m) != EOF){
        build(1,n,1);
        for(int i = 0; i < m; i++){
            int max_value = -1,min_value = 10000000;
            int x,y;
            scanf("%d%d",&x,&y);
            query(1,n,x,y,1,min_value,max_value);
            printf("%d\n",max_value - min_value);
        }
    }
    return 0;
}