HDU 5062 beautiful palindrome number (mathematical problem)

Question link: http://acm.hdu.edu.cn/showproblem.php? PID = 1, 5062

Problem descriptiona positive integer x can represent (A1a2... Akak... A2a1) 10 Or (A1a2... AK? 1 Akak? 1... A2a1) 10 Of a 10-based notational system, we always call X is a palindrome number. If it satisfies 0 <A1 <A2 <... <Ak ≤ 9 , We call X is a beautiful palindrome number.
Now, we want to know how many beautiful palindrome numbers are between 1 and 10n . Inputthe first line in the input file is an integer T (1 ≤ T ≤ 7) , Indicating the number of test cases.
Then T lines follow, each line represent an integer N (0 ≤ n ≤ 6) . Outputfor each test case, output the number of beautiful palindrome number. sample input

216

Sample output

9258

Sourcebestcoder round #13

Question:

Within the range of the N power from 1 to 10, the following conditions are met:

1. It is the number of replies;

2. The first half of the text is in ascending order;

Code for table creation:

# Include <cstdio> # include <cstring> int find_num (INT num) {int A [17]; memset (A, 0, sizeof (a); int L = 0; while (Num) {A [++ L] = num % 10; num/= 10;} For (INT I = 1; I <= l/2; I ++) // return {if (a [I]! = A [L-I + 1]) return 0 ;}for (INT I = 1; I <l/2 + L % 2; I ++) // in ascending order {if (a [I + 1] <= A [I]) return 0;} return 1;} int main () {int sum [17]; memset (sum, 0, sizeof (SUM); sum [0] = 1; for (INT I = 1; I <= 1000000; I ++) {int flag = find_num (I); If (FLAG) {// printf ("Num: % d \ n", I); if (I <= 10) sum [1] ++; if (I <= 100) sum [2] ++; if (I <= 1000) sum [3] ++; if (I <= 10000) sum [4] ++; if (I <= 100000) sum [5] ++; if (I <= 1000000) sum [6] ++ ;}} int t; for (INT I = 0; I <= 6; I ++) {printf ("% d :: % d \ n ", I, sum [I]);} return 0 ;}

The Code is as follows:

#include <cstdio>int main(){    int t;    scanf("%d",&t);    while(t--)    {        int n;        scanf("%d",&n);        if(n == 0)            printf("1\n");        else if(n == 1)            printf("9\n");        else if(n == 2)            printf("18\n");        else if(n == 3)            printf("54\n");        else if(n == 4)            printf("90\n");        else if(n == 5)            printf("174\n");        else if(n == 6)            printf("258\n");    }    return 0;}

HDU 5062 beautiful palindrome number (mathematical problem)