hdu3555 Bomb

链接

与上一个类似，更简单一些，标记前面是否出现过49和4.

#include <iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<stdlib.h>
#include<vector>
#include<cmath>
#include<queue>
#include<set>
using namespace std;
#define N 100000
#define LL long long
#define INF 0xfffffff
const double eps = 1e-8;
const double pi = acos(-1.0);
const double inf = ~0u>>2;
LL n,dp[22][2][2][2];
int d[22];
LL dfs(int i,bool e,bool o,bool p)
{
    if(i==-1)
    {
        if(p) return 1;
        return 0;
    }
    if(!e&&dp[i][e][o][p]!=-1) return dp[i][e][o][p];
    int j;
    int mk = e?d[i]:9;
    LL ans = 0;
    for(j = 0; j <= mk ; j++)
    {
        if(p)
        ans+=dfs(i-1,e&&j==mk,0,1);
        else
        {
            if(o&&j==9)
            ans+=dfs(i-1,e&&j==mk,0,1);
            else
            {
                if(j==4)
                ans+=dfs(i-1,e&&j==mk,1,0);
                else
                ans+=dfs(i-1,e&&j==mk,0,0);
            }
        }
    }
    //cout<<ans<<" "<<i<<endl;
    return e?ans:dp[i][e][o][p]=ans;
}
LL cal(LL x)
{
    int g=0;
    while(x)
    {
        d[g++] = x%10;
        x/=10;
    }
    return dfs(g-1,1,0,0);
}
int main()
{
    int t;
    cin>>t;
    memset(dp,-1,sizeof(dp));
    while(t--)
    {
        cin>>n;
        cout<<cal(n)<<endl;
    }
    return 0;
}