hdu3555 数位dp

#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define INF 99999999
#define ll __int64
using namespace std;
const int MAXN = 30;
ll dp[MAXN][MAXN];
void init()
{
    int i,j,k;
    memset(dp,0,sizeof(dp));
    dp[0][0] = 1;
    for(i=1; i<=25; i++){
        for(j=0; j<=9; j++){
            for(k=0; k<=9; k++){
                if(!(j==4 && k==9)){
                    dp[i][j] += dp[i-1][k];
                }
            }
        }
    }
}
ll slove(ll n)
{
    int i,j,digit[30],len;
    len = 0;
    memset(digit,0,sizeof(digit));
    ll x = n;
    while(1){
        if(!x)break;
        digit[++len] = x%10;
        x/=10;
    }

    ll ans = 0;
    for(i=len; i>0; i--){
        for(j=0; j<digit[i]; j++){
            if(!(digit[i+1]==4 && j==9))
                ans += dp[i][j];
        }
        if(digit[i+1]==4 && digit[i]==9)
            break;
    }
    return ans;
}        
int main()
{
    int i,j,t;
    ll n;
    init();
    cin>>t;
    while(t--){
        cin>>n;
        cout<<n-slove(n+1)+1<<endl;
    }
    return 0;
}
原文地址:https://www.cnblogs.com/sweat123/p/5113290.html