题解 | #自守数#纯C

#include <stdio.h>
#include <string.h>

int main() {
    int num;
    scanf("%d", &num);
    int count = 0;
    for (int i = 0; i <= num; i++) {
       int ret = i * i;
       char str_num[6], str_ret[20];
       sprintf(str_num, "%d", i); //类型转换，将数字转换为字符串以便进行比较
       sprintf(str_ret, "%d", ret);
       int len_num = strlen(str_num);
       int len_ret = strlen(str_ret);
       int tem = 0;
       for (int j = 0; j < len_num; j++) {
        if (str_num[j] == str_ret[len_ret - len_num + j]) {
            tem++;
        }
       }
       if (tem == len_num) {
        count++;
       }
    }
    printf("%d", count);
    
    return 0;
}