P1980 [NOIP2013 普及组] 计数问题

R63298328

Luogu/P1980/P1980.cpp

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, x, ans;
+
+int cntx(int num) {
+    int res = 0;
+    while (num) {
+        res += num % 10 == x;
+        num /= 10;
+    }
+    return res;
+}
+
+int main() {
+    cin >> n >> x;
+    for (int i = 1; i <= n; i++) {
+        ans += cntx(i);
+    }
+    cout << ans << endl;
+    return 0;
+}