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

#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 = 10000 + 5;
const int maxlen = 11;
const int maxnode = maxn * maxlen;
const int sigma_size = 10;

char dict[maxn][maxlen];

struct Trie_Node {
int next[sigma_size],val;
};

Trie_Node node[maxnode];
int trie_sz;

void init() {
trie_sz = 1;
memset(&node[0],0,sizeof(Trie_Node));
}

inline int idx(char c) {
return c - '0';
}

bool insert(char *str) {
int len = strlen(str);
int u = 0;
for(int i = 0;i < len;i++) {
int c = idx(str[i]);
if(node[u].next[c] == 0) {
memset(&node[trie_sz],0,sizeof(Trie_Node));
node[u].next[c] = trie_sz;
node[trie_sz].val = 0;
trie_sz++;
}
u = node[u].next[c];
}
if(node[u].val == 0) node[u].val = 1;
else return false;
return true;
}

bool query(char *str) {
int len = strlen(str);
int u = 0;
for(int i = 0;i < len;i++) {
int c = idx(str[i]);
if(node[u].val == 1) return false;
u = node[u].next[c];
}
return true;
}

int main() {
int t,n; scanf("%d",&t);
while(t--) {
init();
scanf("%d",&n);
bool ok = true;
for(int i = 0;i < n;i++) {
scanf("%s",dict[i]);
ok = ok && insert(dict[i]);
}
for(int i = 0;i < n;i++) {
ok = ok && query(dict[i]);
}
if(ok) puts("YES");
else puts("NO");
}
return 0;
}