Bomb HDU - 3555 数位dp

Posted 2021-03-05 qingyuyyyyy

#include<cstring>
#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
typedef long long ll;
const int N = 35;
ll n;
ll f[N][30];
void init() {
    //处理一位的数字 
    for (int i = 0; i <= 9; i ++ )
        f[1][i] = 1;
    //处理两位数及以上的的数字
    for (int i = 1; i < N; i ++ )
        //最高位
        for (int j = 0; j <= 9; j ++ ) { 
            //次高位 
            for (int k = 0; k <= 9; k ++ ) { 
                if (j == 4 && k == 9) 
                    continue;
                f[i][j] += f[i - 1][k];
            }
        }
}
ll dp(ll n) {
    if (!n) 
        return 1;
    vector<int> nums;
    while (n) 
        nums.push_back(n % 10), n /= 10;
    ll res = 0;
    ll last = 0;//存上一位多少
    for (int i = nums.size() - 1; i >= 0; i -- ) {
        ll x = nums[i];
        for (int j = 0; j < x; j ++ ) {
            if (last == 4 && j == 9) 
                continue;
            //从0到第i位一共i+1位 
            res += f[i + 1][j];
        }
        if (last == 4 && x == 9) 
            break;
        last = x;
        if (!i) 
            res ++ ;
    }
    return res;
}
int main()
{
    ll t;
    cin>>t;
    init();
    while(t--)
    {
        cin>>n;
        cout<<n-dp(n)+1<<endl;
    }
    return 0;
}