#133. 二维树状数组 1：单点修改，区间查询

https://loj.ac/s/1687063

LibreOJ/133/133.cpp

@@ -0,0 +1,63 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = (1 << 12) + 5;
+
+int n, m, op;
+long long c[N][N];
+
+int lowbit(int x) {
+    return x & -x;
+}
+
+void add(int x, int y, int v) {
+    for (int i = x; i <= n; i += lowbit(i)) {
+        for (int j = y; j <= m; j += lowbit(j)) {
+            c[i][j] += v;
+        }
+    }
+}
+
+long long sum(int x, int y) {
+    long long res = 0;
+
+    for (int i = x; i; i -= lowbit(i)) {
+        for (int j = y; j; j -= lowbit(j)) {
+            res += c[i][j];
+        }
+    }
+
+    return res;
+}
+
+long long sum(int x1, int y1, int x2, int y2) {
+    return sum(x2, y2) - sum(x1 - 1, y2) - sum(x2, y1 - 1) + sum(x1 - 1, y1 - 1);
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    while (cin >> op) {
+        if (op == 1) {
+            int x, y, k;
+
+            cin >> x >> y >> k;
+
+            add(x, y, k);
+        } else {  // op == 2
+            int a, b, c, d;
+
+            cin >> a >> b >> c >> d;
+
+            cout << sum(a, b, c, d) << endl;
+        }
+    }
+
+    return 0;
+}