HDU 3943 数位DP

#include <cstdlib>
#include <cctype>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <string>
#include <iostream>
#include <sstream>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <fstream>
#include <numeric>
#include <iomanip>
#include <bitset>
#include <list>
#include <stdexcept>
#include <functional>
#include <utility>
#include <ctime>
#include <cassert>
#include <complex>
using namespace std;
typedef long long ll;
typedef long double ld;
const int int_max = 0x07777777;
const int int_min = 0x80000000;
const int inf=0x20202020;
const ll mod=1000000007;
const double eps=1e-9;
const double pi=3.1415926535897932384626;
const int DX[]={1,0,-1,0},DY[]={0,1,0,-1};
ll powmod(ll a,ll b) {ll res=1;a%=mod;for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll powmod(ll a,ll b,ll mod) {ll res=1;a%=mod;for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll dp[30][21][21];
ll p,q,x,y,a[30];
ll getcount (int len){
    ll sum = 0;
    int xx=0, yy=0;
    for(int i = len; i >= 1; i--){
        for(int j = 0; j <a[i]; j++){
            if(j==4){
                if(xx<x) sum += dp[i-1][x-xx-1][y-yy];
                continue;
            }
            if(j==7) {
                if(yy<y) sum += dp[i-1][x-xx][y-yy-1];
                continue;
            }
            sum += dp[i-1][x-xx][y-yy];
        }
        if(a[i]==4) xx++;
        if(a[i]==7) yy++;
        if(xx>x || yy>y) break;
    }
    return sum;
}
ll solve (ll x){
    for(int i = 0; i < 30; i++) a[i] = 0;
    int len = 0;
    while(x){
        a[++len] = x%10;
        x /= 10;
    }
    ll ret = getcount(len);
    return ret;
}
bool check (ll num){
    int xx = 0, yy = 0;
    while(num){
        int t = num%10;
        if(t==4) xx++;
        if(t==7) yy++;
        num /= 10;
    }
    if(xx==x && yy==y) return true;
    return false;
}
long long Solve(long long k){
    int len=1;
    while(1){
        if(dp[len-1][x][y]<k && dp[len][x][y]>=k)   //找到目标数的长度
            break;
        len++;
    }
    long long res=0;
    int cx=x,cy=y;
    for(int i=len;i>0;i--)   //从高位开始从小枚举
        for(int j=0;j<10;j++){
            int tx=cx,ty=cy;
            if(j==4){
                tx--;
                if(tx<0)
                    continue;
            }
            if(j==7){
                ty--;
                if(ty<0)
                    continue;
            }
            if(dp[i-1][tx][ty]>=k){
                res=res*10+j;
                cx=tx;
                cy=ty;
                break;
            }
            k-=dp[i-1][tx][ty];
        }
    return res;
}
int main()
{
    for(int i = 0; i < 30; i++){
        for(int j = 0; j < 21; j++){
            for(int k = 0; k < 21; k++) dp[i][j][k] = 0;
        }
    }
    dp[0][0][0] = 1;
    for(int i = 1; i < 30; i++){
        for(int j = 0; j < 21; j++){
            for(int k = 0; k <21; k++){
                dp[i][j][k] += dp[i-1][j][k]*8;
                if(j>0) dp[i][j][k] += dp[i-1][j-1][k];
                if(k>0) dp[i][j][k] += dp[i-1][j][k-1];
            }
        }
    }
    int T;
    scanf("%d", &T);
    int cntt = 1;
    while(T--){
        printf("Case #%d:\n",cntt++);
        scanf("%I64d%I64d%I64d%I64d",&p,&q,&x,&y);
        int n;
        scanf("%d", &n);
        ll first = solve(p+1);
        ll second = solve(q+1);
        for(int i = 0; i < n; i++){
            ll k;
            scanf("%I64d",&k);
            int len=1;
            if(first+k > second) {
                printf("Nya!\n");
                continue;
            }
            k = first+k;
            while(1){
            if(dp[len-1][x][y]<k && dp[len][x][y]>=k)   //找到目标数的长度
                break;
            len++;
            }
            long long res=0;
            int cx=x,cy=y;
            for(int i=len;i>0;i--)   //从高位开始从小枚举
                 for(int j=0;j<10;j++){
            int tx=cx,ty=cy;
            if(j==4){
                tx--;
                if(tx<0)
                    continue;
            }
            if(j==7){
                ty--;
                if(ty<0)
                    continue;
            }
            if(dp[i-1][tx][ty]>=k){
                res=res*10+j;
                cx=tx;
                cy=ty;
                break;
            }
            k-=dp[i-1][tx][ty];
        }
            printf("%I64d\n", res);
        }
    }
}