全排列

dfs实现：

//#pragma GCC optimize(2)
#pragma comment(linker, "/STACK:10240000,10240000")
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<ctime>
#include<ctype.h>
#include<stdlib.h>
#include<bitset>
#include<algorithm>
#include<assert.h>
#include<numeric> //accumulate
#define endl "\n"
#define fi first
#define se second
#define forn(i,s,t) for(int i=(s);i<(t);++i)
#define mem(a,b) memset(a,b,sizeof(a))
#define rush() int MYTESTNUM;cin>>MYTESTNUM;while(MYTESTNUM--)
#define debug(x) printf("%d\n",x)
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
#define mp make_pair
#define pb push_back
#define sc(x) scanf("%d",&x)
#define sc2(x,y) scanf("%d%d",&x,&y)
#define sc3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define pf(x) printf("%d\n",x)
#define pf2(x,y) printf("%d %d\n",x,y)
#define pf3(x,y,z) printf("%d %d %d\n",x,y,z)
#define ll long long
#define ull unsigned long long
#define dd double
#define pfs puts("*****")
#define pfk(x) printf("%d ",(x))
#define kpf(x) printf(" %d",(x))
#define pfdd(x) printf("%.5f\n",(x));
#define pfhh printf("\n")
using namespace std;
const ll P=1e9;
ll mul(ll a, ll b){ll ans = 0;for(;b;a=a*2%P,b>>=1) if(b&1) ans=(ans+a)%P;return ans;}
ll qpow(ll a,ll n) {ll r=1%P;for (a%=P;n;a=a*a%P,n>>=1)if(n&1)r=r*a%P;return r;}
ll inv(ll x){return x<=1?1:inv(P%x)*(P-P/x)%P;}
const int maxn=550;
inline int read()
{
    int X=0,w=0; char ch=0;
    while(!isdigit(ch)) {w|=ch=='-';ch=getchar();}
    while(isdigit(ch)) X=(X<<3)+(X<<1)+(ch^48),ch=getchar();
    return w?-X:X;
}
bool vis[maxn+3];
int ma[maxn+3];
int len=0;
string s;
void ddfs(int n)
{
    if(len==n){
      forn(i,0,n) pfk(ma[i]);
      pfhh;
      return;
    }
    for(int i=1;i<=n;++i){
            if(!vis[i]){
                ma[len++]=i;
                vis[i]=1;
                ddfs(n);
                vis[i]=0;
                ma[--len]=-1;
            }
    }
}
int main()
{
    int n;
    while(~sc(n) && n)
    {
        mem(ma,-1);
        len=0;
        ddfs(n);
    }
    return 0;
}

STL  permutation实现:

//#pragma GCC optimize(2)
#pragma comment(linker, "/STACK:10240000,10240000")
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<ctime>
#include<ctype.h>
#include<stdlib.h>
#include<bitset>
#include<algorithm>
#include<assert.h>
#include<numeric> //accumulate
#define endl "\n"
#define fi first
#define se second
#define forn(i,s,t) for(int i=(s);i<(t);++i)
#define mem(a,b) memset(a,b,sizeof(a))
#define rush() int MYTESTNUM;cin>>MYTESTNUM;while(MYTESTNUM--)
#define debug(x) printf("%d\n",x)
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
#define mp make_pair
#define pb push_back
#define sc(x) scanf("%d",&x)
#define sc2(x,y) scanf("%d%d",&x,&y)
#define sc3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define pf(x) printf("%d\n",x)
#define pf2(x,y) printf("%d %d\n",x,y)
#define pf3(x,y,z) printf("%d %d %d\n",x,y,z)
#define ll long long
#define ull unsigned long long
#define dd double
#define pfs puts("*****")
#define pfk(x) printf("%d ",(x))
#define kpf(x) printf(" %d",(x))
#define pfdd(x) printf("%.5f\n",(x));
#define pfhh printf("\n")
using namespace std;
const ll P=1e9;
ll mul(ll a, ll b){ll ans = 0;for(;b;a=a*2%P,b>>=1) if(b&1) ans=(ans+a)%P;return ans;}
ll qpow(ll a,ll n) {ll r=1%P;for (a%=P;n;a=a*a%P,n>>=1)if(n&1)r=r*a%P;return r;}
ll inv(ll x){return x<=1?1:inv(P%x)*(P-P/x)%P;}
const int maxn=550;
inline int read()
{
    int X=0,w=0; char ch=0;
    while(!isdigit(ch)) {w|=ch=='-';ch=getchar();}
    while(isdigit(ch)) X=(X<<3)+(X<<1)+(ch^48),ch=getchar();
    return w?-X:X;
}
bool vis[maxn+3];
int ma[maxn+3];
int len=0;
string s;
int main()
{
    string s;
    while(cin>>s)
    {
        int len=s.length();
        do{
            cout<<s<<endl;
        }while(next_permutation(s.begin(),s.end()));//如果是数组则是next_permutation(s,s+len)
        //prev_permutation(a,a+len);
    }
    return 0;
}