#include #include #pragma GCC target("avx2") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #define SELECTER(_1,_2,_3,SELECT,...) SELECT #define rep1(i,n) for(int i=0;i=0;--i) #define rrep2(i,a,n) for(int i=(int)(n)-1;i>=(int)a;--i) #define rrep(...) RSELECTER(__VA_ARGS__, rrep2, rrep1)(__VA_ARGS__) #define all(a) a.begin(),a.end() #define rall(a) a.rbegin(),a.rend() #define fi first #define se second #define PrintR LogOutput #ifdef _DEBUG #define Log(...) LogOutput(__VA_ARGS__) #else #define Log(...) #endif #define M_PI 3.14159265358979323846 using namespace std; using namespace atcoder; using ll=long long; using ld=long double; using pii=pair; using pll=pair; using pdd=pair; using tp=tuple; using tpll=tuple; using veci=vector; using vecpii=vector>; using vecll=vector; using vecpll=vector>; using vecpdd=vector>; using vecs=vector; using vecb=vector; using vecd=vector; using vectp=vector; using vectpll=vector; using mint=modint998244353; using mint10=modint1000000007; template istream& operator>>(istream& in, pair& a){return in >> a.first >> a.second;} template ostream& operator<<(ostream& out, const pair& a){return out << a.first << ' ' << a.second;} ostream& operator<<(ostream& out, const mint& a){return out << a.val();} ostream& operator<<(ostream& out, const mint10& a){return out << a.val();} ostream& operator<<(ostream& out, const modint& a){return out << a.val();} template ostream& operator<<(ostream& out, const vector& d){for(int i = 0 ; i < d.size() ; ++i) out << d[i] << (i == d.size() - 1 ? "" : " "); return out;} template pair operator+(const pair& a, const pair& b){return {a.fi + b.fi, a.se + b.se};} template pair operator-(const pair& a, const pair& b){return {a.fi - b.fi, a.se - b.se};} template inline bool chmax(T& a,T b){if(a inline bool chmin(T& a,T b){if(a>b) {a=b;return true;} return false;} bool Judge(int i, int j, int h, int w){return i < 0 || j < 0 || i >= h || j >= w;} bool PrintA(int i){cout<<(i ? "Yes" : "No")<::max() >> 2; constexpr int inf=numeric_limits::max() >> 1; constexpr ll MOD=998244353; const int vi[] = {0, 1, 0, -1}, vj[] = {1, 0, -1, 0}; template void LogOutput(Args&&... args){ stringstream ss; ((ss << args << ' '), ...); cout << ss.str().substr(0, ss.str().length() - 1) << endl; } template void LogOutput(vector>& data){for(auto d : data) LogOutput(d);} int main(){ ios::sync_with_stdio(false); std::cin.tie(nullptr); int test;cin>>test; rep(_, test){ int n, lg, k;cin>>n>>lg>>k; lg++; vecll a(n); rep(i, n) cin>>a[i], a[i] += lg; auto f = [&](int m){ vecll t; rep(i, n){ t.push_back(a[i]); t.push_back(a[i] + m + 1); t.push_back(a[i] - m - 1); } sort(all(t)); t.erase(unique(all(t)), t.end()); veci c(t.size() + 1), d(t.size() + 1); auto Idx = [&](ll k){return lower_bound(all(t), k) - t.begin();}; rep(i, n){ c[Idx(a[i])]++; d[Idx(a[i])]++; c[Idx(a[i] + m + 1)]--; d[Idx(a[i] - m - 1)]--; } rep(i, 1, c.size()) c[i] += c[i - 1]; rrep(i, d.size() - 1) d[i] += d[i + 1]; rep(i, t.size()) if(t[i] >= lg && t[i] < 2 * lg){ int r = c[i] + d[i]; int j = upper_bound(all(t), t[i] + lg) - t.begin(); r += c[j - 1]; j = Idx(t[i] - lg); r += d[j]; if(r < k) return 0; } return 1; }; int l = -1, r = lg; while(r - l > 1){ int mid = (l + r) / 2; if(f(mid)) r = mid; else l = mid; } cout<