OpenSoure_Repos/TheAlgorithms-C-Plus-Plus
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This commit is contained in:
MSedra 2021-01-27 23:15:43 +02:00
parent 1033d440da
commit de595b0c19
1 changed files with 17 additions and 11 deletions
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28
range_queries/persistent_segment_tree_with_lazy_propagation.cpp
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@ -14,6 +14,7 @@ private:
Node() { Node() {
val = prop = version = 0; val = prop = version = 0;
left = right = nullptr;
} }
}; };
@ -21,8 +22,9 @@ private:
std::vector<std::shared_ptr<Node>> ptrs; // ptrs[i] holds a root pointer to the segment tree after the ith update std::vector<std::shared_ptr<Node>> ptrs; // ptrs[i] holds a root pointer to the segment tree after the ith update
std::vector<int> vec; std::vector<int> vec;
std::shared_ptr<Node> newKid(std::shared_ptr<Node> curr) { std::shared_ptr<Node> newKid(std::shared_ptr<Node> const &curr) {
std::shared_ptr<Node> newNode(new Node()); //std::shared_ptr<Node> newNode(new Node());
auto newNode = std::make_shared<Node>(Node());
newNode->left = curr->left; newNode->left = curr->left;
newNode->right = curr->right; newNode->right = curr->right;
newNode->prop = curr->prop; newNode->prop = curr->prop;
@ -30,7 +32,7 @@ private:
return newNode; return newNode;
} }
void lazy(int i, int j, std::shared_ptr<Node> curr) { void lazy(int i, int j, std::shared_ptr<Node> const &curr) {
if (!curr->prop) { if (!curr->prop) {
return; return;
} }
@ -46,7 +48,7 @@ private:
} }
void construct(int i, int j, std::shared_ptr<Node> &curr) { void construct(int i, int j, std::shared_ptr<Node> &curr) {
curr = std::shared_ptr<Node>(new Node()); curr = std::make_shared<Node>(Node());
if (i == j) { if (i == j) {
curr->val = vec[i]; curr->val = vec[i];
} else { } else {
@ -57,7 +59,7 @@ private:
} }
} }
std::shared_ptr<Node> update(int i, int j, int l, int r, int value, std::shared_ptr<Node> curr) { std::shared_ptr<Node> update(int i, int j, int l, int r, int value, std::shared_ptr<Node> const &curr) {
lazy(i, j, curr); lazy(i, j, curr);
if (i >= l && j <= r) { if (i >= l && j <= r) {
std::shared_ptr<Node> newNode = newKid(curr); std::shared_ptr<Node> newNode = newKid(curr);
@ -69,7 +71,7 @@ private:
if (i > r || j < l) { if (i > r || j < l) {
return curr; return curr;
} }
std::shared_ptr<Node> newNode = std::shared_ptr<Node>(new Node()); auto newNode = std::make_shared<Node>(Node());
int mid = i + (j - i) / 2; int mid = i + (j - i) / 2;
newNode->left = update(i, mid, l, r, value, curr->left); newNode->left = update(i, mid, l, r, value, curr->left);
newNode->right = update(mid + 1, j, l, r, value, curr->right); newNode->right = update(mid + 1, j, l, r, value, curr->right);
@ -78,7 +80,7 @@ private:
return newNode; return newNode;
} }
int64_t query(int i, int j, int l, int r, std::shared_ptr<Node> curr) { int64_t query(int i, int j, int l, int r, std::shared_ptr<Node> const &curr) {
lazy(i, j, curr); lazy(i, j, curr);
if (j < l || r < i) { if (j < l || r < i) {
return 0; return 0;
@ -95,7 +97,8 @@ public:
n = 0; n = 0;
} }
void construct(const std::vector<int> &vec) // the segment tree will be built from the values in "vec", "vec" is 0 indexed void construct(
const std::vector<int> &vec) // the segment tree will be built from the values in "vec", "vec" is 0 indexed
{ {
if (vec.empty()) { if (vec.empty()) {
return; return;
@ -107,18 +110,21 @@ public:
ptrs.push_back(root); ptrs.push_back(root);
} }
void update(int l, int r, int value) // all elements from index "l" to index "r" would by updated by "value", "l" and "r" are 0 indexed void update(int l, int r,
int value) // all elements from index "l" to index "r" would by updated by "value", "l" and "r" are 0 indexed
{ {
ptrs.push_back(update(0, n - 1, l, r, value, ptrs.push_back(update(0, n - 1, l, r, value,
ptrs[ptrs.size() - 1])); // saving the root pointer to the new segment tree ptrs[ptrs.size() - 1])); // saving the root pointer to the new segment tree
} }
int64_t query(int l, int r, int version) // querying the range from "l" to "r" in a segment tree after "version" updates, "l" and "r" are 0 indexed int64_t query(int l, int r,
int version) // querying the range from "l" to "r" in a segment tree after "version" updates, "l" and "r" are 0 indexed
{ {
return query(0, n - 1, l, r, ptrs[version]); return query(0, n - 1, l, r, ptrs[version]);
} }
int size() // returns the number of segment trees (versions) , the number of updates done so far = returned value - 1 ,because one of the trees is the original segment tree int
size() // returns the number of segment trees (versions) , the number of updates done so far = returned value - 1 ,because one of the trees is the original segment tree
{ {
return ptrs.size(); return ptrs.size();
} }