Querying the Document - Hacker Rank Solution

Querying the Document - Hacker Rank Solution

The true problem here is to write function  from string. Let's write some assisting functions ,  and . They all will take some substring of the original string as a parameter. You can pass the substring itself, however, in order to save time and memory, two indices are recommended instead: the index of the original string where the substring begins and the index of the original string where the substring ends.

All of these functions are written quite similar, so let's look at the pattern of writing them:

1. Let's find out, how many items do we have for the current container. In order to do this, let's count the number of delimeters ( '\n', '.' or ' ') in the substring provided. The number of items is equal to the number of delimeters  with the notable exception for sentences where it's equal to the number of '.' exactly.
2. Now we can allocate memory for the container required. Both  and  will do the thing with the only notable difference in signature.
3. Let's traverse the substring one more time. This time we use a generator for the type of the items in the container (e.g. if we are creating paragraph, then we'll use  for each sentence found out). Store the last index the delimeter was seen and when you meet delimeter one more time, you already know the beginning and the end of a new substring to process.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<assert.h>
#define MAX_CHARACTERS 1005
#define MAX_PARAGRAPHS 5
char* kth_word_in_mth_sentence_of_nth_paragraph(char**** document, int k, int m, int n) {
    return document[n-1][m-1][k-1];
}

char** kth_sentence_in_mth_paragraph(char**** document, int k, int m) { 
    return document[m-1][k-1];
}

char*** kth_paragraph(char**** document, int k) {
    return document[k-1];
}

char* get_word(char* text, int beg, int end) {
    char* answer;
    answer = calloc(end - beg + 2, sizeof(char));
    int index = 0;
    int i;
    for (i = beg; i <= end; i++)
        answer[index++] = text[i];
    answer[index] = 0;
    return answer;
}

char** get_sentence(char* text, int beg, int end) {
    char** answer;
    int word_count = 1;
    int i;
    for (i = beg; i <= end; i++)
        if (text[i] == ' ')
            ++word_count;
    answer = calloc(word_count, sizeof(char*));
    int start = beg;
    int index = 0;
    for (i = beg; i <= end; i++)
        if (text[i] == ' ')
        {
            answer[index++] = get_word(text, start, i - 1);
            start = i + 1;
        }
    answer[index] = get_word(text, start, i - 1);
    return answer;
}

char*** get_paragraph(char* text, int beg, int end) {
    char*** answer;
    int sentence_count = 0;
    int i;
    for (i = beg; i <= end; i++)
        if (text[i] == '.')
            ++sentence_count;
    answer = calloc(sentence_count, sizeof(char**));
    int start = beg;
    int index = 0;
    for (i = beg; i <= end; i++)
        if (text[i] == '.')
        {
            answer[index++] = get_sentence(text, start, i - 1);
            start = i + 1;
        }
    return answer;
}

char**** get_document(char* text) {
    char**** answer;
    int paragraph_count = 1;
    int i;
    for (i = 0; text[i]; i++)
        if (text[i] == '\n')
            ++paragraph_count;
    answer = calloc(paragraph_count, sizeof(char***));
    int start = 0;
    int index = 0;
    for (i = 0; text[i]; i++)
        if (text[i] == '\n')
        {
            answer[index++] = get_paragraph(text, start, i - 1);
            start = i + 1;
        }
    answer[index] = get_paragraph(text, start, i - 1);
    return answer;
}

char* get_input_text() {   
    int paragraph_count;
    scanf("%d", &paragraph_count);

    char p[MAX_PARAGRAPHS][MAX_CHARACTERS], doc[MAX_CHARACTERS];
    memset(doc, 0, sizeof(doc));
    getchar();
    for (int i = 0; i < paragraph_count; i++) {
        scanf("%[^\n]%*c", p[i]);
        strcat(doc, p[i]);
        if (i != paragraph_count - 1)
            strcat(doc, "\n");
    }

    char* returnDoc = (char*)malloc((strlen (doc)+1) * (sizeof(char)));
    strcpy(returnDoc, doc);
    return returnDoc;
}

void print_word(char* word) {
    printf("%s", word);
}

void print_sentence(char** sentence) {
    int word_count;
    scanf("%d", &word_count);
    for(int i = 0; i < word_count; i++){
        printf("%s", sentence[i]);
        if( i != word_count - 1)
            printf(" ");
    }
} 

void print_paragraph(char*** paragraph) {
    int sentence_count;
    scanf("%d", &sentence_count);
    for (int i = 0; i < sentence_count; i++) {
        print_sentence(*(paragraph + i));
        printf(".");
    }
}

int main() {
    char* text = get_input_text();
    char**** document = get_document(text);

    int q;
    scanf("%d", &q);

    while (q--) {
        int type;
        scanf("%d", &type);

        if (type == 3){
            int k, m, n;
            scanf("%d %d %d", &k, &m, &n);
            char* word = kth_word_in_mth_sentence_of_nth_paragraph(document, k, m, n);
            print_word(word);
        }

        else if (type == 2){
            int k, m;
            scanf("%d %d", &k, &m);
            char** sentence = kth_sentence_in_mth_paragraph(document, k, m);
            print_sentence(sentence);
        }

        else{
            int k;
            scanf("%d", &k);
            char*** paragraph = kth_paragraph(document, k);
            print_paragraph(paragraph);
        }
        printf("\n");
    }     
}