http://acm.hdu.edu.cn/showproblem.php?pid=2062
Time Limit: 1000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3569 Accepted Submission(s): 1802
#include <iostream>
#include <cstring>
using namespace std;
typedef unsigned long long ll;
int n;
ll m;
int bit[20],len;
bool used[21];
int fnd(int ind){
int ind2=0;
for(int i=1;i<21;i++){
if(!used[i]){
if(ind==ind2)return i;
ind2++;
}
}
return -1;
}
ll all;
ll dis[21];
int main(){
while(cin>>n>>m){
memset(used,0,sizeof(used));
all =1;
ll sub=1;
for(int i=0;i<n;i++){
sub*=(n-i);
all+=sub;
}
for(int i=0;i<n;i++){
all--;
dis[i]=all/(n-i);
all/=(n-i);
}
len=0;
for(int i=n;i>=1;i--,len++){
if(m==0){break;}
m--;
bit[len]=fnd(m/dis[len]);
used[bit[len]]=true;
m%=dis[len];
}
for(int i=0;i<len;i++){
cout<<bit[i]<<(i==len-1?‘\n‘:‘ ‘);
}
}
return 0;
}
HDU 2062 Subset sequence 数位dp,思路 难度:1
原文:http://www.cnblogs.com/xuesu/p/4296787.html