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Create segment_tree.cpp

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Anthony Wang 2019-07-26 11:17:00 -05:00 committed by GitHub
parent cc9247c856
commit 3859d9ebee
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1 changed files with 70 additions and 0 deletions
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Data Structures/segment_tree.cpp Normal file
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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);
}