I - Olympiad

You are one of the competitors of the Olympiad in numbers. The problem of this year relates to beatiful numbers. One integer is called beautiful if and only if all of its digitals are different (i.e. 12345 is beautiful, 11 is not beautiful and 100 is not beautiful). Every time you are asked to count how many beautiful numbers there are in the interval [a,b] (a≤b)[a,b] (a≤b). Please be fast to get the gold medal! 

InputThe first line of the input is a single integer T (T≤1000)T (T≤1000), indicating the number of testcases. 

For each test case, there are two numbers aa and bb, as described in the statement. It is guaranteed that 1≤a≤b≤1000001≤a≤b≤100000. 
OutputFor each testcase, print one line indicating the answer. 
Sample Input

2
1 10
1 1000

Sample Output

10
738

题目意思:求a 到 b 中各个位数都不相同的数的个数;
解题思路:直接算出1 到 100000 每个数到1中有多少个符合题目意思的数;打表大法好;

#include <iostream>
#include <string.h>
#include <set>
#include <math.h>
using namespace std;

const int MAX = 100000 + 50;
int f[MAX];

int DP_A(int x )
{
    int a[10] = {0};
    for(int i =0;x;x/=10)
    {
        if(a[x%10])
            return 0;
        else
            a[x%10] = 1;
    }
    return 1;

}

void DP()
{
    for(int i = 1;i <= 100000;i++)
    {
        f[i] = f[i -1] + DP_A(i);
    }
}

int main()
{
    DP();
    int N;
    cin>>N;
    while(N--)
    {
        int a,b;
        cin>>a>>b;
        cout<<f[b] - f[a-1]<<endl;
    }

    return 0;
}