简单板子
// Decline is inevitable,
// Romance will last forever.
//#include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <cstring>
#include <string>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <deque>
#include <vector>
using namespace std;
#define mst(a, x) memset(a, x, sizeof(a))
#define INF 0x3f3f3f3f
//#define int long long
const int maxn = 5e4 + 10;
const int P = 1e9 + 7;
int n, q;
int a[maxn];
struct segement_tree {
int l, r;
int mx, mn;
#define mx(x) tree[x].mx
#define mn(x) tree[x].mn
#define l(x) tree[x].l
#define r(x) tree[x].r
}tree[maxn << 2];
void push(int p) {
mn(p) = min(mn(p<<1), mn(p<<1|1));
mx(p) = max(mx(p<<1), mx(p<<1|1));
}
void build(int p, int l, int r) {
l(p) = l; r(p) = r;
if(r == l) {
mx(p) = mn(p) = a[l];
return;
}
int mid = (l + r) >> 1;
build(p<<1, l, mid);
build(p<<1|1, mid + 1, r);
push(p);
}
int query_min(int p, int l, int r) {
if(l <= l(p) && r >= r(p))
return mn(p);
int mid = (l(p) + r(p)) >> 1;
int Min = INF;
if(l <= mid) Min = min(Min, query_min(p<<1, l, r));
if(r > mid) Min = min(Min, query_min(p<<1|1, l, r));
return Min;
}
int query_max(int p, int l, int r) {
if(l <= l(p) && r >= r(p))
return mx(p);
int mid = (l(p) + r(p)) >> 1;
int Max = 0;
if(l <= mid) Max = max(Max, query_max(p<<1, l, r));
if(r > mid) Max = max(Max, query_max(p<<1|1, l, r));
return Max;
}
void solve() {
cin >> n >> q;
for(int i = 1; i <= n; i++)
cin >> a[i];
build(1, 1, n);
while(q--) {
int l, r;
cin >> l >> r;
int Max = query_max(1, l, r);
int Min = query_min(1, l, r);
cout << Max - Min << '\n';
}
}
signed main() {
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
solve();
return 0;
}