Language: C++

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC push_options
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#include<bits/stdc++.h>
#include <xmmintrin.h>
#include <immintrin.h>
using namespace::std;
__attribute__((constructor))void init(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include<ext/pb_ds/tag_and_trait.hpp>
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<0>> cdouble;
// typedef mp::cpp_int cint;
template<typename T>using pbds=__gnu_pbds::tree<T,__gnu_pbds::null_type,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T>using pbds_map=__gnu_pbds::tree<T,T,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T,typename E>using hash_map=__gnu_pbds::gp_hash_table<T,E>;
template<typename T>using pqueue =__gnu_pbds::priority_queue<T, greater<T>,__gnu_pbds::rc_binomial_heap_tag>;
typedef long long lint;
#define INF (1LL<<60)
#define IINF (1<<30)
#define LINF (9223372036854775807LL)
#define EPS (1e-10)
#define endl ('\n')
#define MOD 1000000007LL
//#define MOD 998244353LL
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
template<typename T>inline void numout(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i<INF/2?i:"INF";f=1;}cout<<endl;}
template<typename T>inline void numout2(T t){for(auto i:t)numout(i);}
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void _output(T t){bool f=0;for(lint i=0;i<t.size();i++){cout<<f?"":" "<<t[i];f=1;}cout<<endl;}
template<typename T>inline void _output2(T t){for(lint i=0;i<t.size();i++)output(t[i]);}
#define rep(i,n) for(lint i=0;i<lint(n);++i)
#define repi(i,a,b) for(lint i=lint(a);i<(lint)(b);++i)
#define rrep(i,n) for(lint i=lint(n)-1;i>=0;--i)
#define rrepi(i,a,b) for(lint i=lint(b)-1;i>=lint(a);--i)
#define irep(i) for(lint i=0;;++i)
#define all(n) begin(n),end(n)
#define dist(a,b,c,d) sqrt(pow(a-c,2)+pow(b-d,2))
inline lint gcd(lint A,lint B){return B?gcd(B,A%B):A;}
inline lint lcm(lint A,lint B){return A/gcd(A,B)*B;}
// inline cint cgcd(cint A,cint B){return B?cgcd(B,A%B):A;}
// inline cint clcm(cint A,cint B){return A/cgcd(A,B)*B;}
bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
const vector<lint> dx={1,0,-1,0,1,1,-1,-1};
const vector<lint> dy={0,1,0,-1,1,-1,1,-1};
#define SUM(v) accumulate(all(v),0LL)
auto call=[](auto f,auto... args){return f(f,args...);};

template<typename T>
struct AVL_BASE{
    struct node{
        T val;
        int sz=1,dep=1;
        node* ch[2]={0,0};
        node(T val):val(val){}
        void cpy(node* t){val=t->val;}
    };
    using np=node*;
    int sz(np t){return t?t->sz:0;}
    int dep(np t){return t?t->dep:0;}
    np root=0;
    np update(np t){
        t->sz=sz(t->ch[0])+1+sz(t->ch[1]);
        return t;
    }
    np merge_with_root(np s,np t,np u){
        if(abs(sz(s)-sz(u))<2){
            t->ch[0]=s;t->ch[1]=u;
            return update(t);
        }
        if(sz(s)>sz(u)){
            s->ch[1]=merge_with_root(s->ch[1],t,u);
            return update(s);
        }else{
            u->ch[0]=merge_with_root(s,t,u->ch[0]);
            return update(u);
        }
    }
    np make_root(np& t){
        if(t->ch[1]){
            np res=make_root(t->ch[1]);
            update(t);
            return res;
        }
        else {
            np res=t;
            t=t->ch[0];
            return res;
        }
    }
    np merge(np s,np t){
        if(!s||!t)return s?s:t;
        np u=make_root(s);
        return merge_with_root(s,u,t);
    }
    pair<np,np>split(np t,int i){
        if(!t)return make_pair(nullptr,nullptr);
        np s=t->ch[0],u=t->ch[1];
        t->ch[0]=0;t->ch[1]=0;
        if(i==sz(s)){
            return make_pair(s,merge_with_root(0,t,u));
        }
        if(i<sz(s)){
            auto r=split(s,i);
            return make_pair(r.first,merge_with_root(r.second,t,u));
        }else{
            auto r=split(u,i-sz(s)-1);
            return make_pair(merge_with_root(s,t,r.first),r.second);
        }
    }
    public:
    int size(){return sz(root);}
    void insert(int x,T v){
        assert(0<=x&&x<=size());
        auto s=split(root,x);
        root=merge_with_root(s.first,new node(v),s.second);
    }
    void erase(int x){
        assert(0<=x&&x<size());
        auto s=split(root,x);
        auto t=split(s.second,1);
        root=merge(s.first,t.second);
    }
    T sum(T l,T r){

    }
};

template<typename T>
struct AVL_array:AVL_BASE<T>{
    using AVL_BASE<T>::AVL_BASE;
    void push_back(T v){this->insert(this->size(),v);}
    void pop_back(){this->erase(this->size()-1);}
};

template<typename T>
class segment{
	T* node;
	int n=1;
	public:
	segment(int sz){
		while(n<=sz)n<<=1;
		node=new T[(n<<1)-1];
		for(int i=0;i<(n<<1)-1;i++)node[i]=e;
	}
	segment(const vector<T>& v){
		while(n<(int)v.size())n<<=1;
		node=new T[(n<<1)-1];
		for(int i=0;i<(int)v.size();i++)node[i+n-1]=v[i];
		for(int i=n-2;i>=0;i--)node[i]=f(node[(i<<1)+1],node[(i<<1)+2]);
	}
	T get(lint l,lint r){
		l+=n;r+=n;
		T s=e,t=e;
		while(l<r){
			if(l&1)s=f(s,node[l++-1]);
			if(r&1)t=f(node[--r-1],t);
			l>>=1;r>>=1;
		}
		return f(s,t);
	}
    void change(lint t,T val){
		t+=n-1;
        node[t]=val;
		while(t){
			t=(t-1)>>1;
            node[t]=f(node[t*2+1],node[t*2+2]);
		}
	}
	void update(lint t,T val){
		t+=n-1;
        node[t]=f(node[t],val);
		while(t){
			t=(t-1)>>1;
            node[t]=f(node[t*2+1],node[t*2+2]);
		}
	}
	T e=make_tuple(0,0,0,0,0,0,0);
	T f(const T& s,const T& t){
        lint a,b,c,d,e,f,g,h,i,j,k,l,n,m;
        tie(a,b,c,d,e,f,n)=s;
        tie(g,h,i,j,k,l,m)=t;
        return {min(a,b+g),b+h,a<b+g?c:n+i,max(d,e+j),e+k,d<e+j?f:n+l,n+m};
	}
};


int main(){
    lint x,n;
    cin>>x>>n;
    vec v(n),a(n),b(n);
    rep(i,n){
        cin>>v[i];
    }
    segment<tuple<lint,lint,lint,lint,lint,lint,lint>>seg(n);
    rep(i,n){
        lint t=v[i];
        if(i)t-=v[i-1];
        if(i%2)seg.update(i,make_tuple(0,t,0,0,t,0,1));
        else seg.update(i,make_tuple(0,-t,0,0,-t,0,1));
    }
    lint q;
    cin>>q;
    rep(i,q){
        lint t,a;
        cin>>t>>a;
        auto d=upper_bound(all(v),t);
        if(d==v.begin()){
            cout<<max(0LL,a-t)<<endl;
        }else{
            lint k=d-v.begin();
            auto e=seg.get(0,k);
            lint ans=a+get<1>(e);
            if(get<2>(e)<get<5>(e)){
                if(get<0>(e)+a<0)ans=get<1>(e)-get<0>(e);
                if(x<get<3>(e)+a)ans=get<1>(e)+x-get<3>(e);
            }else{
                if(x<get<3>(e)+a)ans=get<1>(e)+x-get<3>(e);
                if(get<0>(e)+a<0)ans=get<1>(e)-get<0>(e);
            }
            if(k%2){
                cout<<min(x,ans+(t-v[k-1]))<<endl;
            }else{
                cout<<max(0LL,ans-(t-v[k-1]))<<endl;
            }
        }
    }
}

Compiler output:
a.cc:53:12: warning: use of 'auto' in parameter declaration only available with '-std=c++20' or '-fconcepts'
   53 | bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
      |            ^~~~
a.cc:53:26: warning: use of 'auto' in parameter declaration only available with '-std=c++20' or '-fconcepts'
   53 | bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
      |                          ^~~~
a.cc:54:12: warning: use of 'auto' in parameter declaration only available with '-std=c++20' or '-fconcepts'
   54 | bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
      |            ^~~~
a.cc:54:26: warning: use of 'auto' in parameter declaration only available with '-std=c++20' or '-fconcepts'
   54 | bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
      |                          ^~~~
In file included from /usr/include/c++/14/string:43,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:5:
/usr/include/c++/14/bits/allocator.h: In destructor 'std::_Vector_base<long long int, std::allocator<long long int> >::_Vector_impl::~_Vector_impl()':
/usr/include/c++/14/bits/allocator.h:182:7: error: inlining failed in call to 'always_inline' 'std::allocator< <template-parameter-1-1> >::~allocator() noexcept [with _Tp = long long int]': target specific option mismatch
  182 |       ~allocator() _GLIBCXX_NOTHROW { }
      |       ^
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53:
/usr/include/c++/14/bits/stl_vector.h:132:14: note: called from here
  132 |       struct _Vector_impl
      |              ^~~~~~~~~~~~