#pragma GCC optimize ("O3") #include "bits/stdc++.h" using namespace std; using ll = long long int; #define debugos cout #define debug(v) {printf("L%d %s > ",__LINE__,#v);debugos<<(v)<<endl;} #define debugv(v) {printf("L%d %s > ",__LINE__,#v);for(auto e:(v)){debugos<<e<<" ";}debugos<<endl;} #define debuga(m,w) {printf("L%d %s > ",__LINE__,#m);for(int x=0;x<(w);x++){debugos<<(m)[x]<<" ";}debugos<<endl;} #define debugaa(m,h,w) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){debugos<<(m)[y][x]<<" ";}debugos<<endl;}} #define all(v) (v).begin(),(v).end() #define repeat(cnt,l) for(auto cnt=remove_reference<decltype(l)>::type();(cnt)<(l);++(cnt)) #define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt)) #define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt)) #define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt)) const ll MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L; inline void assert_call(bool assertion, function<void()> f) { if (!assertion) { cerr << "assertion fault:" << endl; f(); abort(); } } template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; } template<typename Vec> inline ostream& _ostream_vecprint(ostream& os, const Vec& a) { os << '['; for (const auto& e : a) os << ' ' << e << ' '; os << ']'; return os; } template<typename T> inline ostream& operator<<(ostream& o, const vector<T>& v) { return _ostream_vecprint(o, v); } template<typename T, size_t S> inline ostream& operator<<(ostream& o, const array<T, S>& v) { return _ostream_vecprint(o, v); } template<typename T> inline T& chmax(T& to, const T& val) { return to = max(to, val); } template<typename T> inline T& chmin(T& to, const T& val) { return to = min(to, val); } void bye(string s, int code = 0) { cout << s << endl; exit(code); } mt19937_64 randdev(8901016); template<typename T, typename Random = decltype(randdev), typename enable_if<is_integral<T>::value>::type* = nullptr> inline T rand(T l, T h, Random& rand = randdev) { return uniform_int_distribution<T>(l, h)(rand); } template<typename T, typename Random = decltype(randdev), typename enable_if<is_floating_point<T>::value>::type* = nullptr> inline T rand(T l, T h, Random& rand = randdev) { return uniform_real_distribution<T>(l, h)(rand); } #if defined(_WIN32) || defined(_WIN64) #define getc_x _getc_nolock #define putc_x _putc_nolock #elif defined(__GNUC__) #define getc_x getc_unlocked #define putc_x putc_unlocked #else #define getc_x getc #define putc_x putc #endif #define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E) class MaiScanner { FILE* fp_; public: inline MaiScanner(FILE* fp):fp_(fp){} template<typename T> void input_integer(T& var) noexcept { var = 0; T sign = 1; int cc = getc_x(fp_); for (; cc < '0' || '9' < cc; cc = getc_x(fp_)) if (cc == '-') sign = -1; for (; '0' <= cc && cc <= '9'; cc = getc_x(fp_)) var = (var << 3) + (var << 1) + cc - '0'; var = var * sign; } inline int c() noexcept { return getc_x(fp_); } inline MaiScanner& operator>>(int& var) noexcept { input_integer<int>(var); return *this; } inline MaiScanner& operator>>(long long& var) noexcept { input_integer<long long>(var); return *this; } inline MaiScanner& operator>>(string& var) { int cc = getc_x(fp_); for (; !isvisiblechar(cc); cc = getc_x(fp_)); for (; isvisiblechar(cc); cc = getc_x(fp_)) var.push_back(cc); return *this; } template<typename IT> inline void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; } }; class MaiPrinter { FILE* fp_; public: inline MaiPrinter(FILE* fp):fp_(fp){} template<typename T> void output_integer(T var) noexcept { if (var == 0) { putc_x('0', fp_); return; } if (var < 0) putc_x('-', fp_), var = -var; char stack[32]; int stack_p = 0; while (var) stack[stack_p++] = '0' + (var % 10), var /= 10; while (stack_p) putc_x(stack[--stack_p], fp_); } inline MaiPrinter& operator<<(char c) noexcept { putc_x(c, fp_); return *this; } inline MaiPrinter& operator<<(int var) noexcept { output_integer<int>(var); return *this; } inline MaiPrinter& operator<<(long long var) noexcept { output_integer<long long>(var); return *this; } inline MaiPrinter& operator<<(char* str_p) noexcept { while (*str_p) putc_x(*(str_p++), fp_); return *this; } inline MaiPrinter& operator<<(const string& str) { const char* p = str.c_str(); const char* l = p + str.size(); while (p < l) putc_x(*p++, fp_); return *this; } template<typename IT> void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this << *begin; } }; MaiScanner scanner(stdin); MaiPrinter printer(stdout); template <typename T> class SparseTable { public: int size; vector<int> log2; vector<T> data; vector<T> dp; SparseTable(int size) :size(size), log2(size + 1), data(size) { // for fast calculate log2 for (int i = 2; i <= size; ++i) { log2[i] = log2[i >> 1] + 1; } dp.resize(size*(log2[size] + 1)); } inline T& operator[](size_t i) { return data[i]; } inline T operator[](size_t i)const { return data[i]; } void build() { int l, i, f, b; for (i = 0; i < size; i++) { dp[i] = i; } for (l = 1; (1 << l) <= size; l++) { for (i = 0; i + (1 << l) <= size; i++) { f = dp[i + size * (l - 1)]; b = dp[(i + (1 << (l - 1))) + size * (l - 1)]; dp[i + size * l] = (data[f] <= data[b]) ? f : b; // minimum } } } // range [l,r) int getminrangeIdx(int l, int r) const { int lg = log2[r - l]; int i1 = dp[l + size * lg]; int i2 = dp[r - (1 << lg) + size * lg]; return (data[i1] <= data[i2]) ? i1 : i2; // minimum } }; // int N, K; pair<ll, ll> XA[100010]; // int main() { scanner >> N >> K; --K; repeat(i, N) { ll x; scanner >> x; XA[i].first = x; } repeat(i, N) { ll a; scanner >> a; XA[i].second = a; } SparseTable<ll> lows(N); SparseTable<ll> highs(N); repeat(i, N) { lows[i] = XA[i].first - XA[i].second; highs[i] = -(XA[i].first + XA[i].second); } lows.build(); highs.build(); int li = K; int ri = K+1; repeat(i, N) { int l = lows.getminrangeIdx(li, ri); int r = highs.getminrangeIdx(li, ri); ll left = XA[l].first - XA[l].second; ll right = XA[r].first + XA[r].second; int nli = distance(XA, lower_bound(XA, XA+N, pair<ll,ll>(left, -2e18))); int nri = distance(XA, upper_bound(XA, XA+N, pair<ll,ll>(right, 2e18))); li = nli; ri = nri; } printer << (ri-li) << '\n'; return 0; }