HDU2089 - 不要62

数位DP

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#define MOD ((int)(1e9) + 7)
#define eps 1e-10
using namespace std;
typedef long long ll;
int dp[10][10];
void init() {
    memset(dp, 0, sizeof(dp));
    dp[0][0] = 1;
    for (int i = 1; i <= 7; ++ i) {
        for (int j = 0; j < 10; ++ j) {
            for (int k = 0; k < 10; ++ k) {
                if (j != 4 && !(j == 6 && k == 2))
                    dp[i][j] += dp[i-1][k];
            }
        }
    }
}
int bit[10];
int Dp(int n) {
    int tmp = n;
    for (int i = 1; i <= 8; ++ i) {
        bit[i] = tmp%10;
        tmp /= 10;
    }
    int ans = 0;
    for (int i = 7; i >= 1; -- i) {
        for (int j = 0; j < bit[i]; ++ j) {
            if (j != 4 && !(j == 2 && bit[i+1] == 6))
                ans += dp[i][j];
        }
        if (bit[i] == 4 ||(bit[i] == 2 && bit[i+1] == 6)) break;
    }
    return ans;
}
int main() {
    int n, m;
    init();
    while (scanf("%d%d", &n, &m) != EOF) {
        if (n == 0 && m == 0) break;
        printf("%d\n", Dp(m+1)-Dp(n));
    }
}