242. 一个简单的整数问题

https://www.acwing.com/problem/content/submission/code_detail/13302315/

AcWing/242/242.cpp

@@ -0,0 +1,49 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, m, l, r, d, x, a[N], c[N];
+char op;
+
+inline int lowbit(int x) {
+    return x & -x;
+}
+
+void add(int x, int y) {
+    for (; x <= n; x += lowbit(x)) c[x] += y;
+}
+
+int sum(int x) {
+    int ans = 0;
+    for (; x; x -= lowbit(x)) ans += c[x];
+    return ans;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n >> m;
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    while (m--) {
+        cin >> op;
+
+        if (op == 'C') {
+            cin >> l >> r >> d;
+
+            add(l, d);
+            add(r + 1, -d);
+        } else {  // op == 'Q'
+            cin >> x;
+            cout << a[x] + sum(x) << endl;
+        }
+    }
+
+    return 0;
+}