'commit'

LuoGu/RuMen/P1179.cpp

@@ -0,0 +1,18 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+typedef long long ll;
+
+int main() {
+    ll a, b, s = 0, n;
+    cin >> a >> b;
+    for (ll y = a; y <= b; y++) {
+        n = y;//不能改变循环变量的原值，所以要找“替身”
+        while (n != 0) {
+            if (n % 10 == 2) s++;
+            n /= 10;
+        }
+    }
+    cout << s << endl;
+    return 0;
+}