148 lines
3.6 KiB
C++
148 lines
3.6 KiB
C++
// @link https://www.acwing.com/file_system/file/content/whole/index/content/8807719/
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// Everything starts from 1
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template <typename T> class treap {
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#define lson fhq[u].l
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#define rson fhq[u].r
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private:
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using size_type = size_t;
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using value_type = T;
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using reference = value_type&;
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using const_reference = const reference;
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struct Node {
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int key;
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size_type l, r, size;
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value_type val;
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};
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vector<Node> fhq;
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size_type cnt, root;
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size_type x, y, z;
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size_type _size;
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void pushup(size_type u) {
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fhq[u].size = fhq[lson].size + fhq[rson].size + 1;
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}
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size_type node(value_type val) {
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if (cnt + 1 >= fhq.size()) {
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fhq.push_back({});
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}
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fhq[++cnt].val = val;
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fhq[cnt].key = rand();
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fhq[cnt].size = 1;
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return cnt;
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}
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void split(size_type u, value_type val, size_type &x, size_type &y) {
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if (!u) x = y = 0;
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else {
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if (fhq[u].val <= val) x = u, split(rson, val, rson, y);
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else y = u, split(lson, val, x, lson);
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pushup(u);
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}
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}
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size_type merge(size_type x, size_type y) {
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if (!x || !y) return x + y;
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if (fhq[x].key <= fhq[y].key) {
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fhq[x].r = merge(fhq[x].r, y);
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pushup(x);
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return x;
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} else {
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fhq[y].l = merge(x, fhq[y].l);
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pushup(y);
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return y;
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}
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}
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value_type askNum(size_type u, size_type rank) {
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if (fhq[lson].size + 1 == rank) return fhq[u].val;
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if (fhq[lson].size >= rank) return askNum(lson, rank);
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else return askNum(rson, rank - fhq[lson].size - 1);
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}
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public:
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treap() : fhq(1), cnt(0), root(0), _size(0) {}
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explicit treap(size_type n) : fhq(1), cnt(0), root(0), _size(0) {
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fhq.reserve(n + 1);
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}
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template<typename _InputIterator,
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typename = std::_RequireInputIter<_InputIterator>>
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treap(_InputIterator __first, _InputIterator __last)
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: fhq(1), cnt(0), root(0), _size(0) {
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__try {
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for (; __first != __last; ++__first) {
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insert(*__first);
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}
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} __catch(...) {
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clear();
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__throw_exception_again;
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}
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}
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void clear() {
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_size = root = cnt = 0;
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fill(fhq.begin(), fhq.end(), {});
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}
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void insert(value_type val) {
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assert(!contains(val));
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++_size;
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split(root, val, x, y);
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root = merge(merge(x, node(val)), y);
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}
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void remove(value_type val) {
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assert(contains(val));
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--_size;
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split(root, val, x, z);
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split(x, val - 1, x, y);
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y = merge(fhq[y].l, fhq[y].r);
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root = merge(merge(x, y), z);
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}
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size_type index_of(value_type val) {
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split(root, val - 1, x, y);
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size_type res = fhq[x].size + 1;
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root = merge(x, y);
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return res;
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}
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value_type at(size_type rank) {
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assert(rank > 0 && rank <= _size);
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return askNum(root, rank);
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}
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value_type prev_element(value_type val) {
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split(root, val - 1, x, y);
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size_type u = x;
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while (rson) u = rson;
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root = merge(x, y);
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return fhq[u].val;
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}
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value_type next_element(value_type val) {
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split(root, val, x, y);
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size_type u = y;
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while (lson) u = lson;
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root = merge(x, y);
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return fhq[u].val;
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}
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bool contains(value_type val) {
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size_type idx = index_of(val);
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return idx <= _size && at(idx) == val;
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}
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size_type size() {
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return _size;
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}
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#undef lson
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#undef rson
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};
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