#130. 树状数组 1 ：单点修改，区间查询

https://loj.ac/s/1004202

LibreOJ/130/130.cpp

@@ -0,0 +1,85 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+struct node {
+    int l, r;
+    long long s, d;
+
+    node() {
+        l = r = s = d = 0;
+    }
+    node(int _l, int _r) {
+        l = _l;
+        r = _r;
+        s = d = 0;
+    }
+} tr[1000005 << 2];
+int n, m, op, x, y, k, a[1000005];
+
+void pushup(int u) {
+    tr[u].s = tr[u << 1].s + tr[u << 1 | 1].s;
+}
+
+void pushdown(int u) {
+    if (!tr[u].d) return;
+    tr[u << 1].d += tr[u].d;
+    tr[u << 1].s += (tr[u << 1].r - tr[u << 1].l + 1) * tr[u].d;
+    tr[u << 1 | 1].d += tr[u].d;
+    tr[u << 1 | 1].s += (tr[u << 1 | 1].r - tr[u << 1 | 1].l + 1) * tr[u].d;
+    tr[u].d = 0;
+}
+
+void build(int u, int l, int r) {
+    tr[u] = node(l, r);
+    if (l == r) {
+        tr[u].s = a[l];
+        return;
+    }
+    int mid = l + r >> 1;
+    build(u << 1, l, mid);
+    build(u << 1 | 1, mid + 1, r);
+    pushup(u);
+}
+
+void modify(int u, int l, int r, int d) {
+    if (tr[u].l >= l && tr[u].r <= r) {
+        tr[u].d += d;
+        tr[u].s += (tr[u].r - tr[u].l + 1) * d;
+        return;
+    }
+    int mid = tr[u].l + tr[u].r >> 1;
+    pushdown(u);
+    if (l <= mid) modify(u << 1, l, r, d);
+    if (r > mid) modify(u << 1 | 1, l, r, d);
+    pushup(u);
+}
+
+long long query(int u, int l, int r) {
+    if (tr[u].l >= l && tr[u].r <= r) {
+        return tr[u].s;
+    }
+    int mid = tr[u].l + tr[u].r >> 1;
+    long long s = 0;
+    pushdown(u);
+    if (l <= mid) s += query(u << 1, l, r);
+    if (r > mid) s += query(u << 1 | 1, l, r);
+    return s;
+}
+
+int main() {
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+    build(1, 1, n);
+    for (int i = 0; i < m; i++) {
+        cin >> op >> x >> y;
+        if (op == 1) {
+            modify(1, x, x, y);
+        } else if (op == 2) {
+            cout << query(1, x, y) << endl;
+        }
+    }
+    return 0;
+}