#ifdef LOCAL //#define _GLIBCXX_DEBUG #else #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") //#pragma GCC target("avx512f,avx512dq,avx512cd,avx512bw,avx512vl") #endif #include using namespace std; typedef long long ll; typedef unsigned long long ull; typedef long double ld; typedef pair P; typedef pair Pi; typedef vector Vec; typedef vector Vi; typedef vector Vs; typedef vector Vc; typedef vector

VP; typedef vector VVP; typedef vector VV; typedef vector VVi; typedef vector VVc; typedef vector VVV; typedef vector VVVV; typedef vector VVVVV; typedef vector VVVVVV; #define MAKEVV(variable, a, ...) VV variable(a, Vec(__VA_ARGS__)) #define MAKEVVc(variable, a, ...) VVc variable(a,Vc(__VA_ARGS__)) #define MAKEVVV(variable, a, b, ...) VVV variable(a, VV(b, Vec(__VA_ARGS__))) #define MAKEVVVV(variable, a, b, c, ...) VVVV variable(a, VVV(b, (VV(c, Vec(__VA_ARGS__))))) #define MAKEVVVVV(variable, a, b, c, d, ...) VVVVV variable(a, VVVV(b, (VVV(c, VV(d, Vec(__VA_ARGS__)))))) #define MAKEVVVVVV(variable, a, b, c, d, e, ...) VVVVVV variable(a, VVVVV(b, (VVVV(c, VVV(d, VV(e, Vec(__VA_ARGS__))))))) #define endl '\n' #define REP(i, a, b) for(ll i=(a); i<(b); i++) #define PER(i, a, b) for(ll i=(a); i>=(b); i--) #define rep(i, n) REP(i, 0, n) #define per(i, n) PER(i, n, 0) const ll INF = 4'000'000'000'000'000'010LL; const ll MOD=998244353; #define Yes(n) cout << ((n) ? "Yes" : "No") << endl; #define YES(n) cout << ((n) ? "YES" : "NO") << endl; #define ALL(v) v.begin(), v.end() #define rALL(v) v.rbegin(), v.rend() #define pb(x) push_back(x) #define mp(a, b) make_pair(a,b) #define Each(a,b) for(auto &a :b) #define rEach(i, mp) for (auto i = mp.rbegin(); i != mp.rend(); ++i) #define SUM(a) accumulate(ALL(a),0LL) #define outminusone(a) cout<< ( a==INF ? -1 : a ) <bool chmax(T &a, const S &b) { if (abool chmin(T &a, const S &b) { if (bauto lb(vector &X, T x){return lower_bound(ALL(X),x) - X.begin();} templateauto ub(vector &X, T x){return upper_bound(ALL(X),x) - X.begin();} ll popcnt(ll x){return __builtin_popcount(x);} ll topbit(ll t){return t==0?-1:63-__builtin_clzll(t);} ll floor(ll y,ll x){assert(x != 0);if(x < 0){y *= -1; x *= -1;}if(y < 0){return (y-x+1)/x;}return y/x;}; ll ceil(ll y, ll x){assert(x != 0);if(x < 0){y *= -1; x *= -1;}if(y < 0){return y/x;}return (y+x-1)/x;}; templateistream &operator>>(istream &i, pair &p) { return i>>p.first>>p.second; } templateistream& operator>>(istream&i,vector&v){rep(j,v.size())i>>v[j];return i;} templateostream &operator<<(ostream &s, const pair &p) { return s<<"("<ostream &operator<<(ostream &os, const vector &v) {bool f = false;for(const auto &d: v) {if(f) os<<" ";f = true;os< ostream& operator<<(ostream& os, const set& s) {os << "{";bool f = false;for (auto d : s) {if (f) os << ", ";f = true;os << d;}return os << "}";} template ostream& operator<<(ostream& os, const multiset& s) {os << "{";bool f = false;for (auto d : s) {if (f) os << ", ";f = true;os << d;}return os << "}";} templateostream &operator<<(ostream &os, const map &s) {bool f = false;os< void out(const Head &head, const Tail &...tail) {cout << head;if(sizeof...(tail)) cout << ' ';out(tail...);} #ifdef LOCAL templateostream &operator<<(ostream &s, const vector> &vv) {int len=vv.size();for(int i=0; i auto operator<<(T&& x) {if (!first) os << ", ";first = false;os << x;return *this;}}; template void dbg0(T&&... t) {(PrettyOS{cerr, true} << ... << t);} #define dbg(...)do {cerr << #__VA_ARGS__ << ": ";dbg0(__VA_ARGS__);cerr << endl;} while (false); #else #define dbg(...) #endif int solve(){ ll L; cin>>L; ll n; cin>>n; ll mx = 1e5+10; Vec x(n); cin>>x; Vec y; y.pb(x[0]); rep(i,n-1)y.pb(x[i+1]-x[i]); y.pb(L-x[n-1]); n++; dbg(y); VV dp(2,Vec(2*mx)); dp[0][mx] = 1; rep(i,n){ VV pre(2,Vec(2*mx)); swap(pre,dp); rep(j,mx * 2){ if(j+y[i] < 2*mx and i != n-1){ dp[0][j+y[i]] |= pre[0][j]; //+で取り終わった dp[1][j+y[i]] |= pre[0][j]; } if(j-y[i] >= 0){ dp[0][j-y[i]] |= pre[1][j]; if(i != n-1){ dp[1][j-y[i]] |= pre[1][j]; } } } } ll ans = INF; rep(j,mx * 2){ if(dp[0][j]){ dbg(j); chmin(ans, abs(j-mx)); } } out(ans); return 0; } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); cout<>T; // while(T--) solve(); }