/*  _              _     _                                             _       __      __      __   
   / \     _   _  | |_  | |__     ___    _ __   _    ___   _ __ ___   | | __  / /_    / /_    / /_  
  / _ \   | | | | | __| | '_ \   / _ \  | '__| (_)  / __| | '_ ` _ \  | |/ / | '_ \  | '_ \  | '_ \ 
 / ___ \  | |_| | | |_  | | | | | (_) | | |     _  | (__  | | | | | | |   <  | (_) | | (_) | | (_) |
/_/   \_\  \__,_|  \__| |_| |_|  \___/  |_|    (_)  \___| |_| |_| |_| |_|\_\  \___/   \___/   \___/ 
[Created Time:       2024-11-05 16:30:25]
[Last Modified Time: 2024-11-05 17:01:28] */
#ifdef LOCAL
#include<bits/stdc++.h>
#include"debug.h"
#else
#pragma GCC optimize("Ofast", "unroll-loops")
#include<bits/stdc++.h>
#define D(...) ((void)0)
#endif
using namespace std; using ll = long long;
#define For(i, j, k) for ( int i = (j) ; i <= (k) ; i++ )
#define Fol(i, j, k) for ( int i = (j) ; i >= (k) ; i-- )
namespace FastIO
{
#define USE_FastIO
// ------------------------------
// #define DISABLE_MMAP
// ------------------------------
#if ( defined(LOCAL) || defined(_WIN32) ) && !defined(DISABLE_MMAP)
#define DISABLE_MMAP
#endif
#ifdef LOCAL
	inline void _chk_i() {}
	inline char _gc_nochk() { return getchar(); }
	inline char _gc() { return getchar(); }
	inline void _chk_o() {}
	inline void _pc_nochk(char c) { putchar(c); }
	inline void _pc(char c) { putchar(c); }
	template < int n > inline void _pnc_nochk(const char *c) { for ( int i = 0 ; i < n ; i++ ) putchar(c[i]); }
#else
#ifdef DISABLE_MMAP
	inline constexpr int _READ_SIZE = 1 << 18; inline static char _read_buffer[_READ_SIZE + 40], *_read_ptr = nullptr, *_read_ptr_end = nullptr; static inline bool _eof = false;
	inline void _chk_i() { if ( __builtin_expect(!_eof, true) && __builtin_expect(_read_ptr_end - _read_ptr < 40, false) ) { int sz = _read_ptr_end - _read_ptr; if ( sz ) memcpy(_read_buffer, _read_ptr, sz); char *beg = _read_buffer + sz; _read_ptr = _read_buffer, _read_ptr_end = beg + fread(beg, 1, _READ_SIZE, stdin); if ( __builtin_expect(_read_ptr_end != beg + _READ_SIZE, false) ) _eof = true, *_read_ptr_end = EOF; } }
	inline char _gc_nochk() { return __builtin_expect(_eof && _read_ptr == _read_ptr_end, false) ? EOF : *_read_ptr++; }
	inline char _gc() { _chk_i(); return _gc_nochk(); }
#else
#include<sys/mman.h>
#include<sys/stat.h>
	inline static char *_read_ptr = (char *)mmap(nullptr, [] { struct stat s; return fstat(0, &s), s.st_size; } (), 1, 2, 0, 0);
	inline void _chk_i() {}
	inline char _gc_nochk() { return *_read_ptr++; }
	inline char _gc() { return *_read_ptr++; }
#endif
	inline constexpr int _WRITE_SIZE = 1 << 18; inline static char _write_buffer[_WRITE_SIZE + 40], *_write_ptr = _write_buffer;
	inline void _chk_o() { if ( __builtin_expect(_write_ptr - _write_buffer > _WRITE_SIZE, false) ) fwrite(_write_buffer, 1, _write_ptr - _write_buffer, stdout), _write_ptr = _write_buffer; }
	inline void _pc_nochk(char c) { *_write_ptr++ = c; }
	inline void _pc(char c) { *_write_ptr++ = c, _chk_o(); }
	template < int n > inline void _pnc_nochk(const char *c) { memcpy(_write_ptr, c, n), _write_ptr += n; }
	inline struct _auto_flush { inline ~_auto_flush() { fwrite(_write_buffer, 1, _write_ptr - _write_buffer, stdout); } } _auto_flush;
#endif
#define println println_ // don't use C++23 std::println
	template < class T > inline constexpr bool _is_signed = numeric_limits < T >::is_signed;
	template < class T > inline constexpr bool _is_unsigned = numeric_limits < T >::is_integer && !_is_signed < T >;
#if __SIZEOF_LONG__ == 64
	template <> inline constexpr bool _is_signed < __int128 > = true;
	template <> inline constexpr bool _is_unsigned < __uint128_t > = true;
#endif
	inline bool _isgraph(char c) { return c >= 33; }
	inline bool _isdigit(char c) { return 48 <= c && c <= 57; } // or faster, remove c <= 57
	constexpr struct _table {
#ifndef LOCAL
	int i[65536];
#endif
	char o[40000]; constexpr _table() :
#ifndef LOCAL
	i{},
#endif
	o{} {
#ifndef LOCAL
	for ( int x = 0 ; x < 65536 ; x++ ) i[x] = -1; for ( int x = 0 ; x <= 9 ; x++ ) for ( int y = 0 ; y <= 9 ; y++ ) i[x + y * 256 + 12336] = x * 10 + y;
#endif
	for ( int x = 0 ; x < 10000 ; x++ ) for ( int y = 3, z = x ; ~y ; y-- ) o[x * 4 + y] = z % 10 + 48, z /= 10; } } _table;
	template < class T, int digit > inline constexpr T _pw10 = 10 * _pw10 < T, digit - 1 >;
	template < class T > inline constexpr T _pw10 < T, 0 > = 1;
	inline void read(char &c) { do c = _gc(); while ( !_isgraph(c) ); }
	inline void read_cstr(char *s) { char c = _gc(); while ( !_isgraph(c) ) c = _gc(); while ( _isgraph(c) ) *s++ = c, c = _gc(); *s = 0; }
	inline void read(string &s) { char c = _gc(); s.clear(); while ( !_isgraph(c) ) c = _gc(); while ( _isgraph(c) ) s.push_back(c), c = _gc(); }
	template < class T, bool neg >
#ifndef LOCAL
	__attribute__((no_sanitize("undefined")))
#endif
	inline void _read_int_suf(T &x) { _chk_i(); char c; while
#ifndef LOCAL
	( ~_table.i[*reinterpret_cast < unsigned short *& >(_read_ptr)] ) if constexpr ( neg ) x = x * 100 - _table.i[*reinterpret_cast < unsigned short *& >(_read_ptr)++]; else x = x * 100 + _table.i[*reinterpret_cast < unsigned short *& >(_read_ptr)++]; if
#endif
	( _isdigit(c = _gc_nochk()) ) if constexpr ( neg ) x = x * 10 - ( c & 15 ); else x = x * 10 + ( c & 15 ); }
	template < class T, enable_if_t < _is_signed < T >, int > = 0 > inline void read(T &x) { char c; while ( !_isdigit(c = _gc()) ) if ( c == 45 ) { _read_int_suf < T, true >(x = -( _gc_nochk() & 15 )); return; } _read_int_suf < T, false >(x = c & 15); }
	template < class T, enable_if_t < _is_unsigned < T >, int > = 0 > inline void read(T &x) { char c; while ( !_isdigit(c = _gc()) ); _read_int_suf < T, false >(x = c & 15); }
	inline void write(bool x) { _pc(x | 48); }
	inline void write(char c) { _pc(c); }
	inline void write_cstr(const char *s) { while ( *s ) _pc(*s++); }
	inline void write(const string &s) { for ( char c : s ) _pc(c); }
	template < class T, bool neg, int digit > inline void _write_int_suf(T x) { if constexpr ( digit == 4 ) _pnc_nochk < 4 >(_table.o + ( neg ? -x : x ) * 4); else _write_int_suf < T, neg, digit / 2 >(x / _pw10 < T, digit / 2 >), _write_int_suf < T, neg, digit / 2 >(x % _pw10 < T, digit / 2 >); }
	template < class T, bool neg, int digit > inline void _write_int_pre(T x) { if constexpr ( digit <= 4 ) if ( digit >= 3 && ( neg ? x <= -100 : x >= 100 ) ) if ( digit >= 4 && ( neg ? x <= -1000 : x >= 1000 ) ) _pnc_nochk < 4 >(_table.o + ( neg ? -x : x ) * 4); else _pnc_nochk < 3 >(_table.o + ( neg ? -x : x ) * 4 + 1); else if ( digit >= 2 && ( neg ? x <= -10 : x >= 10 ) ) _pnc_nochk < 2 >(_table.o + ( neg ? -x : x ) * 4 + 2); else _pc_nochk(( neg ? -x : x ) | 48); else { constexpr int cur = 1 << __lg(digit - 1); if ( neg ? x <= -_pw10 < T, cur > : x >= _pw10 < T, cur > ) _write_int_pre < T, neg, digit - cur >(x / _pw10 < T, cur >), _write_int_suf < T, neg, cur >(x % _pw10 < T, cur >); else _write_int_pre < T, neg, cur >(x); } }
	template < class T, enable_if_t < _is_signed < T >, int > = 0 > inline void write(T x) { if ( x >= 0 ) _write_int_pre < T, false, numeric_limits < T >::digits10 + 1 >(x); else _pc_nochk(45), _write_int_pre < T, true, numeric_limits < T >::digits10 + 1 >(x); _chk_o(); }
	template < class T, enable_if_t < _is_unsigned < T >, int > = 0 > inline void write(T x) { _write_int_pre < T, false, numeric_limits < T >::digits10 + 1 >(x), _chk_o(); }
	template < size_t N, class ...T > inline void _read_tuple(tuple < T... > &x) { read(get < N >(x)); if constexpr ( N + 1 != sizeof...(T) ) _read_tuple < N + 1, T... >(x); }
	template < size_t N, class ...T > inline void _write_tuple(const tuple < T... > &x) { write(get < N >(x)); if constexpr ( N + 1 != sizeof...(T) ) _pc(32), _write_tuple < N + 1, T... >(x); }
	template < class ...T > inline void read(tuple < T... > &x) { _read_tuple < 0, T... >(x); }
	template < class ...T > inline void write(const tuple < T... > &x) { _write_tuple < 0, T... >(x); }
	template < class T1, class T2 > inline void read(pair < T1, T2 > &x) { read(x.first), read(x.second); }
	template < class T1, class T2 > inline void write(const pair < T1, T2 > &x) { write(x.first), _pc(32), write(x.second); }
	template < class T > inline auto read(T &x) -> decltype(x.read(), void()) { x.read(); }
	template < class T > inline auto write(const T &x) -> decltype(x.write(), void()) { x.write(); }
	template < class T1, class ...T2 > inline void read(T1 &x, T2 &...y) { read(x), read(y...); }
	template < class ...T > inline void read_cstr(char *x, T *...y) { read_cstr(x), read_cstr(y...); }
	template < class T1, class ...T2 > inline void write(const T1 &x, const T2 &...y) { write(x), write(y...); }
	template < class ...T > inline void write_cstr(const char *x, const T *...y) { write_cstr(x), write_cstr(y...); }
	template < class T > inline void print(const T &x) { write(x); }
	inline void print_cstr(const char *x) { write_cstr(x); }
	template < class T1, class ...T2 > inline void print(const T1 &x, const T2 &...y) { write(x), _pc(32), print(y...); }
	template < class ...T > inline void print_cstr(const char *x, const T *...y) { write_cstr(x), _pc(32), print_cstr(y...); }
	inline void println() { _pc(10); }
	inline void println_cstr() { _pc(10); }
	template < class ...T > inline void println(const T &...x) { print(x...), _pc(10); }
	template < class ...T > inline void println_cstr(const T *...x) { print_cstr(x...), _pc(10); }
}	using FastIO::read, FastIO::read_cstr, FastIO::write, FastIO::write_cstr, FastIO::println, FastIO::println_cstr;
namespace BIT
{
	using T = int; int n; T c[500009];
	inline void init(int x) { n = x, fill(c + 1, c + n + 1, 0); }
	inline void add(int x, T y) { for ( ; x <= n ; x += x & -x ) c[x] += y; }
	// inline T qry(int x) { T y = 0; for ( ; x ; x ^= x & -x ) y += c[x]; return y; }
	// inline T qry(int x, int y) { return qry(y) - qry(x - 1); }
	inline int kth(int x)
	{
		int y = 0; T z = 0;
		Fol(i, 18, 0) if ( ( y | ( 1 << i ) ) <= n && z + c[y | ( 1 << i )] < x )
			z += c[y |= 1 << i];
		return y + 1;
	}
}
int n, m, cc, a[500009], b[500009], l, r, md, pl[500009], pr[500009], cl[500009], cr[500009];
int o, p, q, fa[500009], pre[500009], lenl, lenr; bool used[500009];
tuple < int, int, int > dell[500009], delr[500009];
inline void init(int *a, auto *del, int &len)
{
	iota(pre, pre + m + 2, -1), o = m + 1, len = 0, BIT::init(m);
	For(i, 1, m) BIT::add(i, 1);
	For(i, 1, n) for ( int j = m + 1 - a[i] ; j < o ; del[++len] = tuple(i, p, q), j += cc, o-- )
		p = m + 1 - BIT::kth(j), q = pre[p], pre[p] = pre[q], BIT::add(m + 1 - q, -1), D(p, q);
}
inline void calc(int x, int *a, auto *del, int len, int *p, int *c)
{
	fill(used, used + x + 1, false), fill(used + x + 1, used + m + 1, true),
	iota(fa, fa + x + 1, 0), iota(pre, pre + x + 2, -1), q = 1;
	For(i, 1, n)
	{
		o = 0; 
		for ( int &j = pre[x + 1] ; ~j && o * cc + x < a[i] ; j = pre[j] )
			p[j] = i, c[j] = o++, used[j] = true;
		for ( ; q <= len && get<0>(del[q]) == i ; q++ )
			if ( !used[get<1>(del[q])] && !used[get<2>(del[q])] )
				pre[get<1>(del[q])] = pre[get<2>(del[q])], fa[get<2>(del[q])] = get<1>(del[q]);
	}
	for ( int i = pre[x + 1] ; ~i ; i = pre[i] ) p[i] = n + 1;
	Fol(i, x, 0) p[i] = p[fa[i]], c[i] = c[fa[i]];
}
inline bool chk(int x)
{
	calc(x, a, dell, lenl, pl, cl), calc(x, b, delr, lenr, pr, cr);
	For(i, 0, x) pr[i] = n + 1 - pr[i];
	For(i, 0, x) if ( pl[i] > pr[x - i] || ( pl[i] == pr[x - i] &&
					  x + cc * ( cl[i] + cr[x - i] ) >= a[pl[i]] ) ) return true;
	return false;
}
inline void work()
{
	read(n, m, cc);
	For(i, 1, n) read(a[i]), b[n - i + 1] = a[i];
	init(a, dell, lenl), init(b, delr, lenr);
	for ( l = 0, r = m ; l < r ; ) chk(md = ( l + r ) >> 1) ? r = md : l = md + 1;
	println(l);
}
int main() { int _, t; read(t, _); For(tt, 1, t) work(); return 0; }
// 想上GM捏 想上GM捏 想上GM捏 想上GM捏 想上GM捏
// 伊娜可爱捏 伊娜贴贴捏