#6277. 数列分块入门 1

https://loj.ac/s/1464321

LibreOJ/6277/6277.cpp

@@ -0,0 +1,65 @@
+#include <cmath>
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 50005;
+
+int n, b, a[N], pos[N], st[N], ed[N], add[N];
+
+void change(int l, int r, int d) {
+    int p = pos[l], q = pos[r];
+
+    if (p == q) {
+        for (int i = l; i <= r; i++) {
+            a[i] += d;
+        }
+
+        return;
+    }
+
+    for (int i = p + 1; i <= q - 1; i++) add[i] += d;
+    for (int i = l; i <= ed[p]; i++) a[i] += d;
+    for (int i = st[q]; i <= r; i++) a[i] += d;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n;
+
+    b = std::sqrt(n);
+    for (int i = 1; i <= b; i++) {
+        st[i] = (i - 1) * b + 1;
+        ed[i] = i * b;
+    }
+    if (ed[b] < n) {
+        b++;
+        st[b] = ed[b - 1] + 1;
+        ed[b] = n;
+    }
+
+    for (int i = 1; i <= b; i++) {
+        for (int j = st[i]; j <= ed[i]; j++) {
+            pos[j] = i;
+        }
+    }
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    for (int i = 1, op, l, r, d; i <= n; i++) {
+        cin >> op >> l >> r >> d;
+
+        if (op == 0) {
+            change(l, r, d);
+        } else {  // op == 1
+            cout << a[r] + add[pos[r]] << endl;
+        }
+    }
+
+    return 0;
+}