'commit'

TangDou/AcWing/BIT/P3374.cpp

@@ -0,0 +1,37 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+const int N = 5 * 1e5 + 10;
+int n, m;
+int a[N];
+
+// 树状数组模板
+typedef long long LL;
+#define lowbit(x) (x & -x)
+int c[N];
+void add(int x, int d) {
+    for (int i = x; i < N; i += lowbit(i)) c[i] += d;
+}
+LL sum(int x) {
+    LL res = 0;
+    for (int i = x; i; i -= lowbit(i)) res += c[i];
+    return res;
+}
+
+int main() {
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++)
+        cin >> a[i], add(i, a[i]); // 维护进入树状数组，两个概念：位置，值
+
+    while (m--) {
+        int op, x, y;
+        cin >> op >> x >> y;
+        if (op == 1)
+            add(x, y); // 在x位置上加上y
+        else
+            // 计算[x,y]之间的数字和
+            cout << sum(y) - sum(x - 1) << endl;
+    }
+    return 0;
+}