leetcode

Add Dynamic Segment Tree Recursive implementation

2 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/ README.md b/ README.md

@@ -22,6 +22,7 @@ reference and a base for solving problems. * [Union Find](Templates/Union_Find.cpp): Fast implementation, all optimization tricks used * [Segment Tree Iterative](Templates/segment_tree.cpp): Fast implementation, contains tricky bits * [Segment Tree Recursive](Templates/segment_tree_recursive.cpp): Reference implementation, easy to understand

* [Dynamic Segment Tree Recursive](Templates/segment_tree_dynamic_recursive.cpp): Reference implementation, checks range coverage

## Problems

diff --git a/ Templates/segment_tree_dynamic_recursive.cpp b/ Templates/segment_tree_dynamic_recursive.cpp

@@ -0,0 +1,50 @@

class SegmentTree {

struct Node {

Node *left = nullptr;

Node *right = nullptr;

int low;

int high;

int value;

Node (int low, int high, int value): low(low), high(high), value(value) {}

} root;

void update(Node *root, int l, int r, int val) {

if(root->low == l && root->high == r)

{

root->value = val;

root->left = root->right = NULL; // memory leak

return;

}

const int mid = root->low + (root->high - root->low) / 2;

if(!root->left)

{

root->left = new Node(root->low, mid, root->value);

root->right = new Node(mid + 1, root->high, root->value);

}

if(r <= mid) update(root->left, l, r, val);

else if(l > mid) update(root->right, l, r, val);

else update(root->left, l, mid, val), update(root->right, mid + 1, r, val);

root->value = root->left->value && root->right->value;

}

bool query(const Node *root, int l, int r) const {

if(!root->left) return root->value;

if(root->low == l && root->high == r) return root->value;

const int mid = root->low + (root->high - root->low) / 2;

if(r <= mid) return query(root->left, l, r);

else if(l > mid) return query(root->right, l, r);

return query(root->left, l, mid) && query(root->right, mid + 1, r);

}

public:

SegmentTree(int l, int r, int val): root(l, r, val) {}

void update(int l, int r, int val) { return update(&root, l, r, val); }

bool query(int l, int r) const { return query(&root, l, r); }

};