C. Watto and Mechanism
time limit per test
3 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
Watto, the owner of a spare parts store, has recently got an order for the mechanism that can process strings in a certain way. Initially the memory of the mechanism is filled withnstrings. Then the mechanism should be able to process queries of the following type: "Given strings, determine if the memory of the mechanism contains stringtthat consists of the same number of characters assand differs fromsin exactly one position".
Watto has already compiled the mechanism, all that’s left is to write a program for it and check it on the data consisting ofninitial lines andmqueries. He decided to entrust this job to you.
Input
The first line contains two non-negative numbersnandm(0≤n≤3·105,0≤m≤3·105) — the number of the initial strings and the number of queries, respectively.
Next follownnon-empty strings that are uploaded to the memory of the mechanism.
Next followmnon-empty strings that are the queries to the mechanism.
The total length of lines in the input doesn’t exceed6·105. Each line consistsonlyof letters’a’,’b’,’c’.
Output
For each query print on a single line "YES" (without the quotes), if the memory of the mechanism contains the required string, otherwise print "NO" (without the quotes).
Sample test(s)
input
2 3aaaaaacacacaaabaaccacacccaaac
output
YESNONO
题意：给n个字符串和m次询问，每次询问的字符串如果能够由前面n个字符串中的某一个只改变一个字母得到 输出YES，否则NO。
用字典树解决，渣渣不熟悉字典树，，写在这里以后多看看。。。。
代码：
#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>#include <string>#include <map>#include <stack>#include <vector>#include <set>#include <queue>#pragma comment (linker,"/STACK:102400000,102400000")#define maxn 601005#define MAXN 3#define mod 1000000009#define INF 0x3f3f3f3f#define pi acos(-1.0)#define eps 1e-6#define lson rt<<1,l,mid#define rson rt<<1|1,mid+1,rtypedef long long ll;using namespace std;typedef struct TrieNode{int nCount; //标记该结点是否是某个字符串的结尾struct TrieNode *next[MAXN];}TrieNode;char s[maxn];int n,m;TrieNode *proot;TrieNode *CreateTrieNode() {TrieNode *p;p=(TrieNode *)malloc(sizeof(TrieNode));p->nCount=0;for (int i=0;i<3;i++)p->next[i]=NULL;return p;}void Trie_insert(char *s) //建字典树{TrieNode *p;p=proot;if (!p)p=proot=CreateTrieNode();int i=0;while (s[i]){int k=s[i++]-'a';if (!p->next[k])p->next[k]=CreateTrieNode();p=p->next[k];}p->nCount=1;}bool dfs(TrieNode *root,int len,int flag) //dfs搜索{if (s[len]){int k=s[len]-'a';if (root->next[k]!=NULL){if (dfs(root->next[k],len+1,flag))return true;}if (!flag){for (int i=0;i<3;i++)if (i!=k&&root->next[i]!=NULL)if (dfs(root->next[i],len+1,++flag))return true;}}else{if (flag&&root->nCount==1)return true;}return false;}int main(){while (~scanf("%d%d",&n,&m)){proot=NULL;for (int i=0;i<n;i++){scanf("%s",s);Trie_insert(s);}for (int i=0;i<m;i++){scanf("%s",s);if (dfs(proot,0,0)) printf("YES\n");else printf("NO\n");}}return 0;}
问候不一定要慎重其事，但一定要真诚感人
