diff options
Diffstat (limited to 'datastructures/segmentTree.cpp')
| -rw-r--r-- | datastructures/segmentTree.cpp | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/datastructures/segmentTree.cpp b/datastructures/segmentTree.cpp index 2cbf466..4f75d03 100644 --- a/datastructures/segmentTree.cpp +++ b/datastructures/segmentTree.cpp @@ -4,14 +4,15 @@ struct SegTree { vector<T> tree; static constexpr T E = 0; // Neutral element for combine - SegTree(vector<T>& a) : n(ssize(a)), tree(2 * n) { - //SegTree(int size, T val = E) : n(size), tree(2 * n, val) { + SegTree(vector<T>& a) : n(ssize(a)), tree(2 * n, E) { ranges::copy(a, tree.begin() + n); + //SegTree(int size, T val = E) : n(size), tree(2 * n, E) { + // fill(tree.begin() + n, tree.end(), val); for (int i = n - 1; i > 0; i--) { // remove for range update tree[i] = comb(tree[2 * i], tree[2 * i + 1]); }} - ll comb(T a, T b) {return a + b;} // modify this + neutral + ll comb(T a, T b) { return a + b; } // modify this + neutral void update(int i, T val) { tree[i += n] = val; // apply update code |