'commit'

TangDou/LanQiaoBei/ZhongGaoJi/LanQiao15STEMA202401/str.cpp

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+using namespace std;
+int cnt;
+bool check(int x) {
+    string s = to_string(x);
+    string t = s;
+    reverse(t.begin(), t.end());
+
+    if (s != t) return false;
+    bool flag = false;
+    for (int i = 0; i < s.size(); i++)
+        if (s[i] == '7') flag = true;
+    if (!flag) return false;
+    return true;
+}
+int main() {
+    int a, b;
+    cin >> a >> b;
+    for (int i = a; i <= b; i++)
+        if (check(i)) cnt++;
+    cout << cnt << endl;
+    return 0;
+}