Summer vacation training DAY1 (fishing trie)

trie

Quickly insert and find

template:

int n,m;
int trie[maxn][30],tot=1;
int en[maxn];
string sn;
void inser(string s){
    
    //trie插入
    int ch,len=s.length(),p=1;
    for(int i=0;i<len;i++){
    
    
        ch=s[i]-'a';
        if(trie[p][ch]==0)trie[p][ch]=++tot;
        p=trie[p][ch];
    }
    en[p]=1;
}
int sear(string s){
    
    //检索字符串是否存在
    int len=s.length(),p=1,ch,sum=0;
    for(int i=0;i<len;i++){
    
    
        ch=s[i]-'a';
        p=trie[p][ch];
        if(p==0)return false;
    }
    return en[p];
}

dial

HDU 1671 Phone List, be
careful that maxn is not big enough

int n,m;
int trie[maxn][30],tot=1;
int en[maxn];
char cun[maxn][30];
void inser(char s[]){
    
    //trie插入
    int ch,len=strlen(s),p=1;
    for(int i=0;i<len;i++){
    
    
        ch=s[i]-'0';
        if(trie[p][ch]==0)trie[p][ch]=++tot;
        p=trie[p][ch];
    }
    en[p]++;
}
bool sear(char s[]){
    
    //检索字符串是否存在
    int len=strlen(s),p=1,ch,sum=0;
    for(int i=0;i<len;i++){
    
    
        ch=s[i]-'0';
        p=trie[p][ch];
        if(en[p]==0)continue;
        if(en[p]==1&&i==len-1)continue;
        return false;
    }
    return true;
}
int main(){
    
    
    int t,flag;
    scanf("%d",&t);
    while(t--){
    
    

        flag=1;
        for(int i=1;i<=tot;i++)mem(trie[i],0);
        tot=1;
        mem(en,0);
        sci(n);
        for(int i=1;i<=n;i++){
    
    
            scanf("%s",cun[i]);
            inser(cun[i]);
        }
        for(int i=1;i<=n;i++){
    
    
            if(!sear(cun[i]))flag=0;
        }
        if(flag)puts2();
        else puts3();
    }
    return 0;
}

The xor-longest Path

Difficult

int n, d[N], trie[N*33][2], tot;
vector<pair<int, int> > e[N];
int Head[N], Edge[N*2], Leng[N*2], Next[N*2], num;
bool v[N];

void dfs(int x) {
    
    
	for (int i = Head[x]; i; i = Next[i]) {
    
    
		int y = Edge[i], z = Leng[i];
		if (v[y]) continue;
		v[y] = 1;
		d[y] = d[x] ^ z;
		dfs(y);
	}
}

void add(int x, int y, int z) {
    
    
	Edge[++tot] = y;
	Leng[tot] = z;
	Next[tot] = Head[x];
	Head[x] = tot;
}

void The_xor_longest_Path() {
    
    
	memset(d, 0, sizeof(d));
	memset(trie, 0, sizeof(trie));
	memset(v, 0, sizeof(v));
	memset(Head, 0, sizeof(Head));
	num = 0;
	v[0] = 1;
	tot = 1;
	for (int i = 1; i < n; i++) {
    
    
		int u, v, w;
		scanf("%d %d %d", &u, &v, &w);
		add(u, v, w);
		add(v, u, w);
	}
	dfs(0);
	int ans = 0;
	for (int i = 0; i < n; i++) {
    
    
		int p = 1;
		for (int j = 31; j >= 0; j--) {
    
    
			int k = (d[i] >> j) & 1;
			if (!trie[p][k]) trie[p][k] = ++tot;
			p = trie[p][k];
		}
		p = 1;
		if (i) {
    
    
			int w = 0;
			for (int j = 31; j >= 0; j--) {
    
    
				int k = (d[i] >> j) & 1;
				if (trie[p][k^1]) {
    
    
					w = (w << 1) + (k ^ 1);
					p = trie[p][k^1];
				} else {
    
    
					w = (w << 1) + k;
					p = trie[p][k];
				}
			}
			ans = max(ans, w ^ d[i]);
		}
	}
	cout << ans << endl;
}