#include <iostream>#include <algorithm>#include <numeric>

using namespace std;#define MY_MIN 99999999#define MY_MAX -99999999struct CNode{int L,R;int nMin,nMax;    CNode *pLeft,*pRight;};

int min ( const int a, const int b ) {return (b<a)?b:a;     }int max ( const int a, const int b ) {return (b<a)?a:b;  }

int nMax,nMin; //用于记录最大值和最小值CNode Tree[1000000]; //一般为叶子节点的两倍int nCount=0; //总节点数

void Build(CNode *pRoot,int L,int R){//建线段树

  pRoot->L=L;pRoot->R=R;  pRoot->nMin=MY_MIN;pRoot->nMax=MY_MAX;if(L!=R){     nCount++;     pRoot->pLeft=Tree+nCount;     nCount++;     pRoot->pRight=Tree+nCount;     Build(pRoot->pLeft,L,(L+R)/2);     Build(pRoot->pRight,(L+R)/2+1,R);  } }

void Insert(CNode *pRoot,int i,int v){//将第i个数（其值为v）插入到线段树中    if(pRoot->L==i && pRoot->R==i){        pRoot->nMin=pRoot->nMax=v;return;    }    pRoot->nMax=max(pRoot->nMax,v);    pRoot->nMin=min(pRoot->nMin,v);if(i<=(pRoot->R+pRoot->L)/2){       Insert(pRoot->pLeft,i,v);    }else{       Insert(pRoot->pRight,i,v);    }}

void Query(CNode *pRoot,int L,int R){if( pRoot->nMin>= nMin && pRoot->nMax <= nMax)  //这没理解到。哎。        return;if(pRoot->L==L && pRoot->R==R)    {       nMax=max(pRoot->nMax,nMax);  //这当时也没注意到要用函数。       nMin=min(pRoot->nMin,nMin); return;    }else if(R<=(pRoot->R+pRoot->L)/2){         Query(pRoot->pLeft,L,R);    }else if(L>=(pRoot->R+pRoot->L)/2+1){        Query(pRoot->pRight,L,R);    }else{       Query(pRoot->pLeft,L,(pRoot->R+pRoot->L)/2);       Query(pRoot->pRight,(pRoot->R+pRoot->L)/2+1,R);    }}

int main(){int m,n,x,y;int v,i;    scanf("%d %d",&m,&n);    Build(Tree,1,m);for(i=1;i<=m;i++){        scanf("%d",&v);        Insert(Tree,i,v);    }for(i=1;i<=n;i++){       scanf("%d%d",&x,&y);       nMax = MY_MAX;       nMin = MY_MIN;       Query(Tree,x,y);       printf("%d\n",nMax-nMin);    }return 0;}