#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
using namespace std;

const int INF = 0x3f3f3f3f;
const int N = 50010;
int a[N];

struct Node {
    int l, r, mx, mi;
} tr[N << 2];

int mx, mi;
void pushup(int u) {
    tr[u].mx = max(tr[u << 1].mx, tr[u << 1 | 1].mx);
    tr[u].mi = min(tr[u << 1].mi, tr[u << 1 | 1].mi);
}
void build(int u, int l, int r) {
    tr[u].l = l, tr[u].r = r; // POJ对于tr[u]={l,r}报编译错误，编译器版本太低，需要手动实现构造函数

    if (l == r) {
        tr[u].mx = a[l], tr[u].mi = a[l];
        return;
    }
    int mid = (l + r) >> 1;
    build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
    pushup(u);
}

void query(int u, int l, int r) {
    if (l <= tr[u].l && r >= tr[u].r) {
        mx = max(mx, tr[u].mx), mi = min(mi, tr[u].mi);
        return;
    }

    int mid = (tr[u].l + tr[u].r) >> 1;

    if (l <= mid) query(u << 1, l, r);
    if (r > mid) query(u << 1 | 1, l, r);
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("POJ3264.in", "r", stdin);
#endif
    // 加快读入
    ios::sync_with_stdio(false), cin.tie(0);
    int n, q;
    cin >> n >> q;
    for (int i = 1; i <= n; i++) cin >> a[i];
    build(1, 1, n);

    while (q--) {
        mx = -INF, mi = INF;
        int l, r;
        cin >> l >> r;
        query(1, l, r);
        printf("%d\n", mx - mi);
    }
    return 0;
}