Add template for segment tree

Author: coderick14

segtree.cpp

@@ -0,0 +1,83 @@
+#include <bits/stdc++.h>
+#define MAXN 100000
+
+vector<int> seg(4 * MAXN + 2), lazy(4 * MAXN + 2);
+
+int left(int i) {
+	return 2*i+1;
+}
+
+int right(int i) {
+	return 2*i+2;
+}
+
+void propagate(int idx) {
+	seg[idx] += lazy[idx];
+	lazy[left(idx)] += lazy[idx];
+	lazy[right(idx)] += lazy[idx];
+	lazy[idx] = 0;
+}
+
+void radd(int ql, int qr, int val, int l, int r, int idx) {
+	if (l > r) return;
+	if (l != r) propagate(idx);
+
+	if (ql > r or qr < l) return;
+
+	if (ql <= l and r <= qr) {
+		lazy[idx] += val;
+		if (l != r) propagate(idx);
+		return;
+	}
+
+	int m = l + (r - l) / 2;
+	radd(ql, qr, val, l, m, left(idx));
+	radd(ql, qr, val, m+1, r, right(idx));
+}
+
+void radd(int ql, int qr, int val, int n) {
+	radd(ql, qr, val, 0, n-1, 0);
+}
+
+int pquery(int pos, int l, int r, int idx) {
+	if (l == r) {
+		seg[idx] += lazy[idx];
+		lazy[idx] = 0;
+		return seg[idx];
+	}
+	propagate(idx);
+	int m = l + (r - l) / 2;
+	if (pos <= m) return pquery(pos, l, m, left(idx));
+	return pquery(pos, m+1, r, right(idx));
+}
+
+int pquery(int pos, int n) {
+	return pquery(pos, 0, n-1, 0);
+}
+
+void add(int pos, int val, int l, int r, int idx) {
+	if (l == r) {
+		seg[idx] += val;
+		return;
+	}
+	int m = l + (r - l) / 2;
+	if (pos <= m) add(pos, val, l, m, left(idx));
+	else add(pos, val, m+1, r, right(idx));
+	seg[idx] += val;
+}
+
+void add(int pos, int val, int n) {
+	add(pos, val, 0, n-1, 0);
+}
+
+int query(int ql, int qr, int l, int r, int idx) {
+	if (ql > r or qr < l or l > r) return 0;
+	if (ql <= l and r <= qr) return seg[idx];
+	if (l == r) return seg[l];
+	int m = l + (r - l) / 2;
+	return query(ql, qr, l, m, left(idx)) + query(ql, qr, m+1, r, right(idx));
+}
+
+int query(int ql, int qr, int n) {
+	return query(ql, qr, 0, n-1, 0);
+}