1 #include <iostream> 2 #include <algorithm> 3 #include <cstdio> 4 #include <string> 5 #include <string> 6 #include <cstring> 7 #include <map> 8 #include <utility> 9 using namespace std; 10 const int N = 1e2+20 ; 11 bool vis[N]; 12 int a[N],n; 13 void dfs(int num,int n){ 14 if(num==n){ 15 for(int i =0;i<n;i++){ 16 printf("%d%c",a[i],i==n-1?' ':' '); 17 } 18 return ; 19 } 20 for(int i=1;i<=n;i++){ 21 if(!vis[i]){ 22 vis[i]=1; 23 a[num]=i; 24 dfs(num+1,n); 25 vis[i]=0; 26 } 27 } 28 } 29 int main() 30 { 31 while(~scanf("%d",&n)){ 32 memset(vis,0,sizeof(vis)); 33 dfs(0,n); 34 } 35 return 0; 36 }
1 //用于生成全排列的函数 2 int a[N],n; 3 void init() 4 { 5 for(int i=0;i<4;i++){ 6 a[i]=i+1; 7 } 8 } 9 int main() 10 { 11 init(); 12 int cnt=0; 13 do{ 14 for(int i=0;i<4;i++) 15 printf("%d%c",a[i],i==3?' ':' '); 16 cnt++; 17 }while(next_permutation(a,a+4)); 18 printf("%d ",cnt); 19 return 0; 20 }
1 //从1到n取出m个数 2 #include <iostream> 3 #include <algorithm> 4 #include <cstdio> 5 #include <string> 6 #include <string> 7 #include <cstring> 8 #include <map> 9 #include <utility> 10 using namespace std; 11 const int N = 1e2+20 ; 12 bool vis[N]; 13 int n,m,a[N]; 14 void dfs(int num,int n){ 15 if(num==m+1){ 16 for(int i =1;i<=m;i++) 17 { 18 printf("%d%c",a[i],i==m?' ':' '); 19 } 20 return ; 21 } 22 for(int i =a[num-1]+1;i<=n;i++){ 23 if(!vis[i]){ 24 vis[i]=1; 25 a[num]=i; 26 dfs(num+1,n); 27 vis[i]=0; 28 } 29 } 30 } 31 int main() 32 { 33 while(~scanf("%d%d",&n,&m)){ 34 memset(vis,0,sizeof(vis)); 35 dfs(1,n); 36 } 37 return 0; 38 }
1 //有重复字符的全排列 2 3 #include <cstdio> 4 #include <cstdlib> 5 #include <cstring> 6 #include <iostream> 7 #include <algorithm> 8 using namespace std; 9 const int N=1e3+9; 10 char s[N],buf[N]; 11 int l; 12 bool vis[N]; 13 void dfs(int num){ 14 if(num==l){ 15 printf("%s ",buf); 16 return ; 17 } 18 for(int i =0;i<l;i++){ 19 if(!vis[i]){ 20 int j; 21 for(j=i+1;j<l;j++){ 22 if(vis[j]&&s[i]==s[j]){//重复：先用了s靠后的字符又满足字符一样 23 break; 24 } 25 } 26 if(j==l){ 27 vis[i]=1; 28 buf[num]=s[i]; 29 dfs(num+1); 30 vis[i]=0; 31 } 32 } 33 } 34 35 } 36 int main() 37 { 38 while(~scanf("%s",s)){ 39 memset(vis,0,sizeof(vis)); 40 l =strlen(s); 41 buf[l]=' '; 42 dfs(0); 43 } 44 return 0; 45 } 46 47 48 49 112 50 112 51 121 52 211
1 //hdu 1016 2 3 4 5 #include <cstdio> 6 #include <cstdlib> 7 #include <cstring> 8 #include <iostream> 9 #include <algorithm> 10 using namespace std; 11 const int N=1e2+9; 12 int n; 13 bool vis[N]; 14 int a[N]; 15 bool prime(int n){ 16 if(n==1) return false; 17 for(int i =2;i*i<=n;i++){ 18 if(n%i==0) return false; 19 } 20 return true; 21 } 22 void dfs(int num,int n){ 23 if(num==n&&prime(1+a[n-1])){ 24 for(int i =0;i<n;i++){ 25 printf("%d%c",a[i],i==n-1?' ':' '); 26 } 27 return ; 28 } 29 for(int i=2;i<=n;i++){//1一定是第一个 30 if(!vis[i]&&prime(i+a[num-1])){ 31 vis[i]=1; 32 a[num]=i; 33 dfs(num+1,n); 34 vis[i]=0; 35 } 36 } 37 } 38 int f=1; 39 int main() 40 { 41 while(~scanf("%d",&n)){ 42 memset(vis,0,sizeof(vis)); 43 a[0]=1; 44 printf("Case %d: ",f++); 45 dfs(1,n); 46 printf(" "); 47 } 48 return 0; 49 }
1 #include<cstdio> 2 #include<algorithm> 3 #include<cstring> 4 #include<cmath> 5 #include<iostream> 6 #include<vector> 7 #include <cstdlib> 8 #include <map> 9 using namespace std; 10 #define mem(a,b) memset(a,b,sizeof(a)) 11 const int N = 2e5+5; 12 pair<int,int>P; 13 vector<int> ve[N]; 14 vector<pair<int,int> > que[N]; 15 int a[N],b[N]; 16 int m; 17 int n,sum; 18 bool vis[N]; 19 int cnt = 0; 20 map<int,int>mp; 21 //从数组b里面取出若干个数，令其和为110 22 void dfs(int num,int n){ 23 { 24 if(num<=n&&sum==110) 25 { 26 27 28 29 30 31 32 33 34 for(int j=1;j<=num-1;j++){ 35 printf("%d ",a[j]); 36 } 37 printf(":: %d ",sum); 38 39 return ; 40 } 41 for(int i =mp[a[num-1]]+1;i<=n;i++){ 42 if(!vis[i]){ 43 vis[i] = 1; 44 a[num]= b[i]; 45 sum+=b[i]; 46 dfs(num+1,n); 47 vis[i] = 0; 48 sum-=b[i]; 49 } 50 } 51 } 52 } 53 int main() 54 { 55 sum =0; 56 mp[0]=0; 57 // scanf("%d%d",&n,&m); 58 scanf("%d",&n); 59 for(int i =1;i<=n;i++){ 60 scanf("%d",&b[i]); 61 mp[b[i]] =i; 62 } 63 dfs(1,n); 64 return 0; 65 }