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Add subtree size updating during treap split

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This commit is contained in:
Matúš Púll 2025-03-28 16:16:47 +01:00
parent 7f528796c0
commit 02bdb353a4
1 changed files with 16 additions and 10 deletions
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26
file.hpp
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@ -28,19 +28,21 @@ class file {
}
// Split treap by k-th element
// TODO with sizes
// Hopefully with sizes
two_lines split(line *l, count_type k) {
if(l == nullptr) return {nullptr, nullptr};
if(l->size < k) {
auto two = split(l->right, k);
l->right = two.first;
return {l, two.second};
if(get_size(l->left) > k) {
// In the left subtree
auto two = split(l->left, k);
l->size -= two.first->size;
return {two.first, l};
}
else {
auto two = split(l->left, k - 1 - get_size(l->left));
l->left = two.second;
return {two.first, l};
// In the right subtree
auto two = split(l->right, k - (1+get_size(l->left)));
l->size -= two.second->size;
return {l, two.second};
}
}
// Join two treaps
@ -68,7 +70,7 @@ class file {
if(k >= get_size(l->left))
return find(l->left, k);
else if(k > l->size+1)
return find(l->right, k - 1 - get_size(l->left));
return find(l->right, k - (1+get_size(l->left)) );
else
return l;
}
@ -79,7 +81,11 @@ public:
root = nullptr;
}
// Don't find index k, but k-th line -> +1
line* find(count_type k) {return find(root, k+1);}
line* find(count_type k) {
if(k >= root->size)
return nullptr;
return find(root, k+1);
}
// File access
void insert(int k, string s) {