Create segment_tree.cpp

Changes

1 changed files (+70/-0)

• Data Structures/segment_tree.cpp (new)
  • @@ -0,0 +1,70 @@
    + using namespace std; + constexpr auto MAX_N = 100005; + + int A[MAX_N], seg[4 * MAX_N], tmp[4 * MAX_N]; + + void build(int node, int start, int end) { + if (start == end) seg[node] = A[start]; + else { + int mid = (start + end) >> 1; + build(node << 1, start, mid); + build((node << 1) + 1, mid + 1, end); + seg[node] = seg[node << 1] + seg[(node << 1) + 1]; + } + } + + void update(int node, int start, int end, int idx, int val) { + if (start == end) seg[node] += val; + else { + int mid = (start + end) >> 1; + (start <= idx && idx <= mid) ? update((node << 1), start, mid, idx, val) : update((node << 1) + 1, mid + 1, end, idx, val); + seg[node] = seg[node << 1] + seg[(node << 1) + 1]; + } + } + + int query(int node, int start, int end, int left, int right) { + if (left > end || right < start) return 0; + if (left <= start && right >= end) return seg[node]; + int mid = (start + end) >> 1; + return query(node << 1, start, mid, left, right) + query((node << 1) + 1, mid + 1, end, left, right); + } + + void update_range(int node, int start, int end, int left, int right, int val) { + if (tmp[node]) { + seg[node] += (end - start + 1) * tmp[node]; + if (start != end) { + tmp[node << 1] += tmp[node]; + tmp[(node << 1) + 1] += tmp[node]; + } + tmp[node] = 0; + } + if (start > end || left > end || right < start) return; + if (left <= start && right >= end) { + seg[node] += (end - start + 1) * val; + if (start != end) { + tmp[node << 1] += val; + tmp[(node << 1) + 1] += val; + } + } + else { + int mid = (start + end) >> 1; + update_range(node << 1, start, mid, left, right, val); + update_range((node << 1) + 1, mid + 1, end, left, right, val); + seg[node] = seg[node << 1] + seg[(node << 1) + 1]; + } + } + + int query_range(int node, int start, int end, int left, int right) { + if (start > end || left > end || right < start) return 0; + if (tmp[node]) { + seg[node] += (end - start + 1) * tmp[node]; + if (start != end) { + tmp[node << 1] += tmp[node]; + tmp[(node << 1) + 1] += tmp[node]; + } + tmp[node] = 0; + } + if (left <= start && right >= end) return seg[node]; + int mid = (start + end) >> 1; + return query_range(node << 1, start, mid, left, right) + query_range((node << 1) + 1, mid + 1, end, left, right); + }