teamnote history merge

2025fall/source/DS/SegmentTree.cpp

@@ -0,0 +1,36 @@
+struct Data{
+    ll sum, lazy;
+    constexpr Data(ll m):sum(m), lazy(){}
+    constexpr Data(ll sum, ll lazy):sum(sum), lazy(lazy){}
+};
+Data join(Data A, Data B) {return A.sum+B.sum;}
+using Seg = vector<Data>;
+
+void init(Seg& seg, int i, int s, int e, ll *A) {
+    if(s == e) {seg[i] = A[s]; return;}
+    int mid = (s+e)>>1;
+    init(seg, i*2, s, mid, A); init(seg, i*2+1, mid+1, e, A);
+    seg[i] = join(seg[i*2], seg[i*2+1]);
+}
+void prop(Seg& seg, int i, int s, int e) {
+    seg[i].sum += seg[i].lazy * (e-s+1);
+    if(s != e) for(auto t:{i*2, i*2+1}) seg[t].lazy += seg[i].lazy;
+    seg[i].lazy = 0;
+}
+
+void update(Seg& seg, int i, int s, int e, int a, int b, ll v) {
+    prop(seg, i, s, e);
+    if(e<a||b<s) return;
+    if(a<=s&&e<=b) {seg[i].lazy+=v; prop(seg, i, s, e); return;}
+    int mid = (s+e)>>1;
+    update(seg, i*2, s, mid, a, b, v); update(seg, i*2+1, mid+1, e, a, b, v);
+    seg[i] = join(seg[i*2], seg[i*2+1]);
+}
+
+ll query(Seg& seg, int i, int s, int e, int a, int b) {
+    prop(seg, i, s, e);
+    if(e<a||b<s) return 0;
+    if(a<=s&&e<=b) return seg[i].sum;
+    int mid = (s+e)>>1;
+    return query(seg, i*2, s, mid, a, b) + query(seg, i*2+1, mid+1, e, a, b);
+}