poj 1056 IMMEDIATE DECODABILITY & poj 3630 Phone List
给你一些01串，判断是否会出现其中一个串刚好是另外一个串的前缀。
数据规模比较小，不过为了练习trie还是用了trie
先把所有的01串都插入到树中，然后依次查找每一个串，看路径上是否有别的串
#include <cstdio> #include <sstream> #include <fstream> #include <cstring> #include <iostream> #include <algorithm> #include <map> #include <cctype> #include <ctime> #include <set> #include <climits> #include <vector> #include <queue> #include <stack> #include <cstdlib> #include <cmath> #include <string> #include <list> #define INPUT_FILE "in.txt" #define OUTPUT_FILE "out.txt" using namespace std; typedef long long LL; const int INF = INT_MAX / 2; void setfile() { freopen(INPUT_FILE,"r",stdin); freopen(OUTPUT_FILE,"w",stdout); } const int maxn = 105; const int maxlen = 205; const int maxnode = maxn * maxlen + 5; const int sigma_size = 2; char dict[maxn][maxlen]; bool dok = true; struct Trie { int ch[maxnode][sigma_size],val[maxnode * sigma_size],sz; Trie() { sz = 1; memset(ch[0],0,sizeof(ch[0])); } void clear() { sz = 1; memset(ch,0,sizeof(ch)); memset(val,0,sizeof(val)); } inline int idx(char c) { return c - '0'; } void insert(char *str) { int len = strlen(str); int u = 0; for(int i = 0;i < len;i++) { int c = idx(str[i]); if(ch[u][c] == 0) { memset(ch[sz],0,sizeof(ch[sz])); val[sz] = 0; ch[u][c] = sz++; } u = ch[u][c]; } if(val[u] == 0) { val[u] = 1; } else dok = false; } bool query(char *str) { int len = strlen(str); int u = 0; for(int i = 0;i < len;i++) { int c = idx(str[i]); if(val[u] == 1) return false; u = ch[u][c]; } return true; } }; Trie trie; int main() { int kase = 1,cnt = 0; while(~scanf("%s",dict[cnt++])) { if(dict[cnt - 1][0] != '9') { trie.insert(dict[cnt - 1]); } else { bool ok = true; for(int i = 0;i < cnt - 1 && ok;i++) { ok = ok && trie.query(dict[i]); } if(ok && dok) { printf("Set %d is immediately decodable\n",kase++); } else { printf("Set %d is not immediately decodable\n",kase++); } dok = true; trie.clear(); cnt = 0; } } return 0; }
poj 3630把01串改成了电话号码，完全一样的思路囧
1 #include <cstdio> 2 #include <sstream> 3 #include <fstream> 4 #include <cstring> 5 #include <iostream> 6 #include <algorithm> 7 #include <map> 8 #include <cctype> 9 #include <ctime> 10 #include <set> 11 #include <climits> 12 #include <vector> 13 #include <queue> 14 #include <stack> 15 #include <cstdlib> 16 #include <cmath> 17 #include <string> 18 #include <list> 19 20 #define INPUT_FILE "in.txt" 21 #define OUTPUT_FILE "out.txt" 22 23 using namespace std; 24 25 typedef long long LL; 26 const int INF = INT_MAX / 2; 27 28 void setfile() { 29 freopen(INPUT_FILE,"r",stdin); 30 freopen(OUTPUT_FILE,"w",stdout); 31 } 32 33 const int maxn = 10000 + 5; 34 const int maxlen = 11; 35 const int maxnode = maxn * maxlen; 36 const int sigma_size = 10; 37 38 char dict[maxn][maxlen]; 39 40 struct Trie_Node { 41 int next[sigma_size],val; 42 }; 43 44 Trie_Node node[maxnode]; 45 int trie_sz; 46 47 void init() { 48 trie_sz = 1; 49 memset(&node[0],0,sizeof(Trie_Node)); 50 } 51 52 inline int idx(char c) { 53 return c - '0'; 54 } 55 56 bool insert(char *str) { 57 int len = strlen(str); 58 int u = 0; 59 for(int i = 0;i < len;i++) { 60 int c = idx(str[i]); 61 if(node[u].next[c] == 0) { 62 memset(&node[trie_sz],0,sizeof(Trie_Node)); 63 node[u].next[c] = trie_sz; 64 node[trie_sz].val = 0; 65 trie_sz++; 66 } 67 u = node[u].next[c]; 68 } 69 if(node[u].val == 0) node[u].val = 1; 70 else return false; 71 return true; 72 } 73 74 bool query(char *str) { 75 int len = strlen(str); 76 int u = 0; 77 for(int i = 0;i < len;i++) { 78 int c = idx(str[i]); 79 if(node[u].val == 1) return false; 80 u = node[u].next[c]; 81 } 82 return true; 83 } 84 85 int main() { 86 int t,n; scanf("%d",&t); 87 while(t--) { 88 init(); 89 scanf("%d",&n); 90 bool ok = true; 91 for(int i = 0;i < n;i++) { 92 scanf("%s",dict[i]); 93 ok = ok && insert(dict[i]); 94 } 95 for(int i = 0;i < n;i++) { 96 ok = ok && query(dict[i]); 97 } 98 if(ok) puts("YES"); 99 else puts("NO"); 100 } 101 return 0; 102 }
