poj3252数位dp

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <climits>
#include <string>
#include <iostream>
#include <map>
#include <cstdlib>
#include <list>
#include <set>
#include <queue>
#include <stack>
#include<math.h>
using namespace std;
int dp[55][55][55];
int up[100];
int dfs(int now,int len0,int len1,int flag)
{
    if(now==-1) return len0>=len1;
    if(!flag&&dp[now][len0][len1]!=-1) return dp[now][len0][len1];
    int limit= flag?up[now ]:1 ,ret=0 ;
    for(int i = 0;i <= limit;i++){
        int len00=len0;int len11=len1;
        if(i==0&&len1) len00=len0+1;
        if(i==1) len11=len1+1;
        ret+=dfs(now-1,len00,len11,flag&&i==limit) ;
    }
    if(!flag) dp[now][len0][len1]=ret;
    return ret;
}
int solve(int x)
{
    int len=-1;
    while(x){
        up[++len]=x%2;
        x/=2;
    }
    return dfs(len,0,0,1);
}
int main()
{
    int n, m;
    memset(dp,-1,sizeof(dp));
    while(cin>>n>>m){
        cout<<solve(m) - solve(n-1)<<endl;
    }
    return 0;
}

poj3252数位dp