题目：http://poj.org/problem?id=3007
题意：按照图示的改变字符串，问有多少种。。字符串。。
思路：分几种排序的方法，，刚开始用map 超时（map效率不高啊。。），后来搜了一下题解，用二叉排序树。。。
先贴AC代码：
1 #include <iostream> 2 #include <cstring> 3 #include <algorithm> 4 using namespace std; 5 6 typedef struct tree 7 { 8 char str[100]; 9 struct tree *l,*r; 10 }tr; 11 tr head; 12 int check(char s[]) 13 { 14 tr *q; 15 tr *p=&head; 16 while(p) 17 { 18 if(strcmp(p->str,s)>0) 19 { 20 if(p->l) 21 p=p->l; 22 else 23 { 24 q=new tr; 25 strcpy(q->str,s); 26 q->l=NULL; 27 q->r=NULL; 28 p->l=q; 29 return 1; 30 } 31 } 32 else if(strcmp(p->str,s)<0) 33 { 34 if(p->r) 35 p=p->r; 36 else 37 { 38 q=new tr; 39 strcpy(q->str,s); 40 q->l=NULL; 41 q->r=NULL; 42 p->r=q; 43 return 1; 44 } 45 } 46 else 47 return 0; 48 } 49 return 0; 50 } 51 /*void pre(tr *qqq) 52 { 53 if(qqq) 54 { 55 cout<<qqq->str<<endl; 56 pre(qqq->l); 57 pre(qqq->r); 58 } 59 }*/ 60 int main() 61 { 62 int t,i,j,len,cou,sum; 63 char s[100],s1[100]; 64 cin>>t; 65 while(t--) 66 { 67 cin>>s; 68 strcpy(head.str,s); 69 head.l=NULL; head.r=NULL; 70 sum=1; 71 len=strlen(s); 72 for(i=1; i<len; i++) 73 { 74 cou=0; 75 for(j=0; j<i; j++) 76 s1[cou++]=s[j]; 77 for(j=len-1; j>=i; j--) 78 s1[cou++]=s[j]; 79 s1[cou]=' '; 80 if(check(s1)) 81 sum++; 82 83 cou=0; 84 for(j=len-1; j>=i; j--) 85 s1[cou++]=s[j]; 86 for(j=0; j<i; j++) 87 s1[cou++]=s[j]; 88 s1[cou]=' '; 89 if(check(s)) 90 sum++; 91 92 cou=0; 93 for(j=i-1; j>=0; j--) 94 s1[cou++]=s[j]; 95 for(j=len-1; j>=i; j--) 96 s1[cou++]=s[j]; 97 s1[cou]=' '; 98 if(check(s1)) 99 sum++; 100 101 cou=0; 102 for(j=len-1; j>=i; j--) 103 s1[cou++]=s[j]; 104 for(j=i-1; j>=0; j--) 105 s1[cou++]=s[j]; 106 s1[cou]=' '; 107 if(check(s1)) 108 sum++; 109 110 cou=0; 111 for(j=0; j<i; j++) 112 s1[cou++]=s[j]; 113 for(j=i; j<=len-1; j++) 114 s1[cou++]=s[j]; 115 s1[cou]=' '; 116 if(check(s1)) 117 sum++; 118 119 cou=0; 120 for(j=i; j<=len-1; j++) 121 s1[cou++]=s[j]; 122 for(j=0; j<i; j++) 123 s1[cou++]=s[j]; 124 s1[cou]=' '; 125 if(check(s1)) 126 sum++; 127 128 cou=0; 129 for(j=i-1; j>=0; j--) 130 s1[cou++]=s[j]; 131 for(j=i; j<=len-1; j++) 132 s1[cou++]=s[j]; 133 s1[cou]=' '; 134 if(check(s1)) 135 sum++; 136 137 cou=0; 138 for(j=i; j<=len-1; j++) 139 s1[cou++]=s[j]; 140 for(j=i-1; j>=0; j--) 141 s1[cou++]=s[j]; 142 s1[cou]=' '; 143 if(check(s1)) 144 sum++; 145 146 cou=0; 147 for(j=len-1; j>=i; j--) 148 s1[cou++]=s[j]; 149 for(j=0; j<=i-1; j++) 150 s1[cou++]=s[j]; 151 s1[cou]=' '; 152 if(check(s1)) 153 sum++; 154 } 155 cout<<sum<<endl; 156 //tr *qqq; 157 //qqq=&head; 158 //pre(qqq); 159 } 160 return 0; 161 }
再贴一下map超时的。。
1 #include <iostream> 2 #include <cstring> 3 #include <map> 4 #include <algorithm> 5 using namespace std; 6 7 int main() 8 { 9 int t,i,j,len,cou,sum; 10 char s[100],s1[100]; 11 int f; 12 cin>>t; 13 while(t--) 14 { 15 map<string,int>mp; 16 map<string,int>::iterator iter; 17 cin>>s; 18 sum=0; 19 len=strlen(s); 20 for(i=1; i<len; i++) 21 { 22 cou=0; 23 for(j=0; j<i; j++) 24 s1[cou++]=s[j]; 25 for(j=len-1; j>=i; j--) 26 s1[cou++]=s[j]; 27 s1[cou]=' '; 28 f=0; 29 iter=mp.begin(); 30 while(iter!=mp.end()) 31 { 32 if(iter->first==s1) 33 { 34 f=1; 35 break; 36 } 37 iter++; 38 } 39 if(f==0) 40 { 41 sum++; 42 mp[s1]=1; 43 } 44 cou=0; 45 for(j=len-1; j>=i; j--) 46 s1[cou++]=s[j]; 47 for(j=0; j<i; j++) 48 s1[cou++]=s[j]; 49 s1[cou]=' '; 50 f=0; 51 iter=mp.begin(); 52 while(iter!=mp.end()) 53 { 54 if(iter->first==s1) 55 { 56 f=1; 57 break; 58 } 59 iter++; 60 } 61 if(f==0) 62 { 63 sum++; 64 mp[s1]=1; 65 } 66 67 cou=0; 68 for(j=i-1; j>=0; j--) 69 s1[cou++]=s[j]; 70 for(j=len-1; j>=i; j--) 71 s1[cou++]=s[j]; 72 s1[cou]=' '; 73 f=0; 74 iter=mp.begin(); 75 while(iter!=mp.end()) 76 { 77 if(iter->first==s1) 78 { 79 f=1; 80 break; 81 } 82 iter++; 83 } 84 if(f==0) 85 { 86 sum++; 87 mp[s1]=1; 88 } 89 90 cou=0; 91 for(j=len-1; j>=i; j--) 92 s1[cou++]=s[j]; 93 for(j=i-1; j>=0; j--) 94 s1[cou++]=s[j]; 95 s1[cou]=' '; 96 f=0; 97 iter=mp.begin(); 98 while(iter!=mp.end()) 99 { 100 if(iter->first==s1) 101 { 102 f=1; 103 break; 104 } 105 iter++; 106 } 107 if(f==0) 108 { 109 sum++; 110 mp[s1]=1; 111 } 112 113 cou=0; 114 for(j=0; j<i; j++) 115 s1[cou++]=s[j]; 116 for(j=i; j<=len-1; j++) 117 s1[cou++]=s[j]; 118 s1[cou]=' '; 119 f=0; 120 iter=mp.begin(); 121 while(iter!=mp.end()) 122 { 123 if(iter->first==s1) 124 { 125 f=1; 126 break; 127 } 128 iter++; 129 } 130 if(f==0) 131 { 132 sum++; 133 mp[s1]=1; 134 } 135 136 cou=0; 137 for(j=i; j<=len-1; j++) 138 s1[cou++]=s[j]; 139 for(j=0; j<i; j++) 140 s1[cou++]=s[j]; 141 s1[cou]=' '; 142 f=0; 143 iter=mp.begin(); 144 while(iter!=mp.end()) 145 { 146 if(iter->first==s1) 147 { 148 f=1; 149 break; 150 } 151 iter++; 152 } 153 if(f==0) 154 { 155 sum++; 156 mp[s1]=1; 157 } 158 cou=0; 159 for(j=i-1; j>=0; j--) 160 s1[cou++]=s[j]; 161 for(j=i; j<=len-1; j++) 162 s1[cou++]=s[j]; 163 s1[cou]=' '; 164 f=0; 165 iter=mp.begin(); 166 while(iter!=mp.end()) 167 { 168 if(iter->first==s1) 169 { 170 f=1; 171 break; 172 } 173 iter++; 174 } 175 if(f==0) 176 { 177 sum++; 178 mp[s1]=1; 179 } 180 181 cou=0; 182 for(j=i; j<=len-1; j++) 183 s1[cou++]=s[j]; 184 for(j=i-1; j>=0; j--) 185 s1[cou++]=s[j]; 186 s1[cou]=' '; 187 f=0; 188 iter=mp.begin(); 189 while(iter!=mp.end()) 190 { 191 if(iter->first==s1) 192 { 193 f=1; 194 break; 195 } 196 iter++; 197 } 198 if(f==0) 199 { 200 sum++; 201 mp[s1]=1; 202 } 203 } 204 cout<<sum<<endl; 205 } 206 return 0; 207 }