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TangDou/CSP-J/BiShuaTi/meiju/P2010_int.cpp

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+// https://www.luogu.com.cn/problem/P2010
+#include <bits/stdc++.h>
+
+using namespace std;
+
+//月份日期常数数组
+int months[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+
+//判断是不是闰年
+bool LeapYear(int year) {
+    return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
+}
+//是不是回文字符串
+bool isHW(string s) {
+    string t = s;
+    reverse(t.begin(), t.end());
+    return s == t;
+}
+
+int cnt;
+int main() {
+    int st, ed;
+    cin >> st >> ed;
+
+    int y1 = st / 10000;
+    int y2 = ed / 10000;
+
+    //枚举年份
+    for (int i = y1; i <= y2; i++)
+        // 枚举月份
+        for (int j = 1; j <= 12; j++) {
+            //枚举日期
+            int day = months[j];
+            if (LeapYear(i) && j == 2) day = 29; //闰年二月份，共29天
+            for (int k = 1; k <= day; k++) {
+                int s = i * 10000 + j * 100 + k;
+                //与范围字符串st,ed进行比较，如果不在范围内，continue
+                if (s < st || s > ed) continue; //日期字符串符合字典序
+                //判断是不是回文
+                char x[10];
+                sprintf(x, "%d", s);
+                if (isHW(x)) cnt++;
+            }
+        }
+    //输出
+    printf("%d\n", cnt);
+    return 0;
+}