字典树-trie

hdu-1075

描述：将火星文翻译成英文。

反思：好久以前做的，现在又拿来写了个字典树，递归比非递归确实慢，一个小错误导致wa数次。

 

#include <stdio.h>
#include <string.h>
#include <ctype.h>

struct Node {
    Node *t[26];
    char mar[13];
    Node () {
        for (int i=0; i<26; i++)
            t[i] = NULL;
        mar[0] = '\0'; //key '\0' 写成了 '/0'
    }
};

Node *head;

void build(Node *p, char *c1, char *c2) {
    if (*c1 == '\0') {
        strcpy(p->mar, c2);
        return;
    }
    int k = *c1-'a';
    if (p->t[k] == NULL) {
        p->t[k] = new Node;
    }
    build(p->t[k], c1+1, c2);
}

void find(Node *p, char *c1, char *c2) {
    if (*c1 == '\0') {
        if (p->mar[0] != '\0')
            strcpy(c2, p->mar);
        return;
    }
    int k = *c1-'a';
    if (p->t[k] != NULL) {
        find(p->t[k], c1+1, c2);
    }
}

int main()
{
    char c1[20], c2[20], c[3010];
//    freopen("datain", "r", stdin);
//    freopen("dataout", "w", stdout);
    while (scanf("%s", c1) != EOF) {
        head = new Node;
        while (scanf("%s", c1)) {

            if (strcmp(c1,"END") == 0) break;
            scanf("%s", c2);

            build(head, c2, c1);
        }
        scanf("%s%*c", c1);
        while (gets(c)) {
            if (strcmp(c, "END") == 0) break;
            int len = strlen(c);
            for (int i=0; i<len; ) {
                int j = 0;
                while (i<len && isalpha(c[i])) {
                    c1[j++] = c[i++];
                }
                if (j>0) {
                    c1[j] = '\0';
                    c2[0] = '\0';
                    find(head, c1, c2);
                    if (c2[0] != '\0') {
                        printf("%s", c2);
                    }else {
                        printf("%s", c1);
                    }
                }else {
                    printf("%c", c[i]);
                    i++;
                }
            }
            printf("\n");
        }
    }
    return 0;
}

 

hdu-1251

描述：求前缀中包含给定串的单词数。

变形：结点记录的信息是建树时经过该结点的次数。

 

hdu-1298

描述：手机智能拼音输入法[见题]

反思：strcmp()函数搞错，wa数次，查错过错很纠结！

 

#include <stdio.h>
#include <string.h>

struct Node {
    Node * t[26];
    int per;

    Node() {
        for (int i = 0; i < 26; i++) {
            t[i] = NULL;
        }
        per = 0;
    }
};
char ans[110], cc[110];
int pp;
Node *head;
char dg[10][5] = {
    {},
    {},
    {3, 'a', 'b', 'c'},
    {3, 'd', 'e', 'f'},
    {3, 'g', 'h', 'i'},
    {3, 'j', 'k', 'l'},
    {3, 'm', 'n', 'o'},
    {4, 'p', 'q', 'r', 's'},
    {3, 't', 'u', 'v'},
    {4, 'w', 'x', 'y', 'z'}
};

void build(Node *p, char *c, int per) {
    p->per += per;
    if (*c == '\0') return;
    int k = *c - 'a';
    if (p->t[k] == NULL) {
        p->t[k] = new Node;
    }
    build(p->t[k], c + 1, per);
}

void find(Node *p, char *c, char *c1) {
    if (*c == '\0') {
        *c1 = '\0';
        if (ans[0] == '\0') {
            strcpy(ans, cc);
            pp = p->per;
        } else {
            if (p->per > pp) {
                strcpy(ans, cc);
                pp = p->per;
            } else if (p->per == pp) {
                if (strcmp(ans, cc) > 0) { //key 写成 ‘<’ 了
                    strcpy(ans, cc);
                }
            }
        }
        return;
    }
    int k = *c - '0';
    for (int i = 1; i <= dg[k][0]; i++) {
        int j = dg[k][i] - 'a';
        if (p->t[j] == NULL) continue;
        *c1 = dg[k][i];
        find(p->t[j], c + 1, c1 + 1);
    }
}

int main() {
//    freopen("datain", "r", stdin);
//    freopen("dataout", "w", stdout);
    int t, cs = 1;
    int w, m, i, j, per;
    char c[130], dig[110];
    scanf("%d", &t);
    while (t--) {
        head = new Node;
        scanf("%d", &w);
        while (w--) {
            scanf("%s%d", c, &per);
            build(head, c, per);
        }
        printf("Scenario #%d:\n", cs++);
        scanf("%d", &m);
        while (m--) {
            scanf("%s", dig);
            int len = strlen(dig);
            for (i = 1; i < len; i++) {
                char c0[110], c1[110];
                strncpy(c0, dig, i);
                c0[i] = '\0';                
                ans[0] = '\0';
                pp = 0;
         //       printf("%s ", c0);
                find(head, c0, cc);
         //       ans[i] = '\0';
                if (ans[0] == '\0') {
                    printf("MANUALLY\n");
                } else {
                    printf("%s\n", ans);
                }
            }
            printf("\n");
        }
        printf("\n");
    }
    return 0;
}

 

 

zju-1109

描述：同hdu-1075.

Say_Sth:这次用非递归写的，当然比递归的快点，可以当模板。

#include <stdio.h>
#include <string.h>
#define F 26 //字符集规模
#define M 13 //单词最大长度

struct Node {
    Node *t[F];
    char word[M]; //结点保存的信息
    Node () { //initicalize
        for (int i=0; i<F; i++) {
            t[i] = NULL;
        }
        word[0] = 0;
    }
};
Node *head;

void build(Node *p, char *c1, char *c2) {
    Node *p1 = p;
    while (*c1) {
        int k = *c1-'a';
        if (p1->t[k] == 0) p1->t[k] = new Node;
        p1 = p1->t[k];
        c1++;
    }
    strcpy(p1->word, c2);
}

bool find(Node *p, char *c1, char *c2) {
    Node *p1 = p;
    while (*c1) {
        int k = *c1-'a';
        if (p1->t[k]) p1 = p1->t[k];
        else return false;
        c1++;
    }
    strcpy(c2, p1->word);
    return true;
}

int main()
{
//    freopen("datain", "r", stdin);
    char c[M*3], c1[M], c2[M];
    head = new Node;
    while (gets(c)) {
        if (!strcmp(c,"")) break;
        sscanf(c, "%s%s", c1, c2);
        build(head, c2, c1);
    }
    while (scanf("%s", c1) != EOF) {
        if (find(head, c1, c2)) {
            printf("%s\n", c2);
        }else {
            printf("eh\n");
        }
    }
    return 0;
}