P2602 [ZJOI2010] 数字计数

https://www.luogu.com.cn/record/85802739

Luogu/P2602/P2602.cpp

@@ -0,0 +1,62 @@
+#include <iostream>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+long long a, b,
+    f[15], g[15]{1},
+    cnt_a[10], cnt_b[10];
+
+std::vector<int> gen(long long x) {
+    std::vector<int> res;
+
+    while (x) {
+        res.push_back(x % 10);
+        x /= 10;
+    }
+
+    return res;
+}
+
+void calc(long long x, long long* r) {
+    auto num = gen(x);
+
+    for (int i = num.size(); i; i--) {
+        for (int j = 0; j < 10; j++) {
+            r[j] += f[i - 1] * num.at(i - 1);
+        }
+
+        for (int j = 0; j < num[i - 1]; j++) {
+            r[j] += g[i - 1];
+        }
+
+        x -= g[i - 1] * num[i - 1];
+        r[num[i - 1]] += x + 1;
+        r[0] -= g[i - 1];
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> a >> b;
+
+    for (int i = 1; i <= 12; i++) {
+        f[i] = f[i - 1] * 10 + g[i - 1];
+        g[i] = g[i - 1] * 10;
+    }
+
+    calc(a - 1, cnt_a);
+    calc(b, cnt_b);
+
+    for (int i = 0; i < 10; i++) {
+        cout << cnt_b[i] - cnt_a[i] << ' ';
+    }
+
+    cout << endl;
+
+    return 0;
+}