Given an input dictionary read in from a file to use for all test cases, and several word search grids, i want to identify all words from the dictionary that appear in each word search grid.
I have read in the dictionary.txt file and I believe it can read in any grid of letters, I am having trouble trying to find the words in the grid that appear in the dictionary.txt file. I decided to use a recursive binary search on the string of characters going in all directions but it is a bit complicated for me.
My program runs until it gets to the word searching function where it tries to find the words in the grid and it'll crash but I dont know why and not sure if i am on the right track.
here is the piece i think is wrong,
int binsearch(char** dictionary, char** puzzle, int low, int high){
int mid;
if(low == 0 && high == 0){
return 0;
}
mid = (low+high)/2 ;
if(strcmp(*puzzle,dictionary[mid]) == 0){
//found a match
return 1;
}
else if(strcmp(*puzzle,dictionary[mid]) > 0){
//check upper half
return binsearch(dictionary,puzzle,mid+1,high);
}
else if(strcmp(*puzzle,dictionary[mid]) < 0){
//check lower half
return binsearch(dictionary,puzzle,low,mid-1);
}
else return 0;
}
char wordSearch(char** dictionary, char** puzzle, int row, int col){
int i, X, Y, dir = 0;
char* wordsfound[20]= {'\0'};
for (X=0;X<row+1;X++){
for(Y=0;Y<col;Y++){
for(dir=0;dir<DX_SIZE;dir++) //check every direction
for(i=0;i<19;i++){
//will continue in direction DX,DY starting at x,y
int nextX = X + DX[dir] * i;
int nextY = Y + DY[dir] * i;
if(nextX < 0 || nextX >= row) break; //keep in bounds
if(nextY < 0 || nextY >= col) break;
//store the string of letters
*wordsfound[i] = (puzzle[nextX][nextY]);
if(i>2){ //minimum word is 3
//if the string of letters is actually a word, print
int bin = binsearch(dictionary,wordsfound,1,listlength);
if(bin){
printf("%s\n",wordsfound);
}
}
}
}
}
}
but here is my entire code
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define listlength 149256
#define maxWordLen 19
char** getWords(int rows, int cols);
void freeArray(char** array, int rows);
char** makeGridArray(int rows, int cols);
int binsearch(char** dictionary, char** puzzle, int low, int high);
char wordSearch(char** dictionary, char** puzzle, int row, int col);
const int DX_SIZE = 8;
const int DX[] = {-1,-1,-1,0,0,1,1,1};
const int DY[] = {-1,0,1,-1,1,-1,0,1};
int main(){
//read in dictionary
int i,j,x=0, numCases, gridRow, gridCol;
char** words = getWords(listlength, maxWordLen);
//Get number of cases.
printf("enter number of cases:\n");
scanf("%d", &numCases);
//process each case.
while(x < numCases){
scanf("%d%d",&gridRow,&gridCol);
//make word search grid
char** grid = makeGridArray(gridRow+1, gridCol);
/* for testing if grid is storing properly
for(i=0; i<gridRow+1;i++){
printf("%s\n",grid[i]);
}
*/
printf("Words Found Grid #%d:",x+1);
wordSearch(words, grid, gridRow+1, gridCol);
x++;
freeArray(grid,gridRow+1);
}
freeArray(words, listlength);
}
char** getWords(int rows, int cols){
int i;
//allocate top level of pointers.
char** words = malloc(sizeof(char*)*rows);
//allocate each individual array
for(i=0; i<rows; i++){
words[i] = malloc(sizeof(char)*cols+1);
}
//read dictionary.txt
FILE *dictionary = fopen("dictionary.txt", "r");
for(i=0; i<rows; i++){
fgets(words[i], cols+1,dictionary);
}
fclose(dictionary);
return words;
}
char** makeGridArray(int rows, int cols){
//allocate top level of pointers.
char** grid = malloc(sizeof(char*)*rows);
int i,j;
//allocate each individual array
for(i=0; i<rows;i++){
grid[i] = malloc(sizeof(char)*cols+1);
}
//read in user input grid
for(i=0;i<rows;i++){
gets(grid[i]);
}
return grid;
}
int binsearch(char** dictionary, char** puzzle, int low, int high){
int mid;
if(low == 0 && high == 0){
return 0;
}
mid = (low+high)/2 ;
if(strcmp(*puzzle,dictionary[mid]) == 0){
//found a match
return 1;
}
else if(strcmp(*puzzle,dictionary[mid]) > 0){
//check upper half
return binsearch(dictionary,puzzle,mid+1,high);
}
else if(strcmp(*puzzle,dictionary[mid]) < 0){
//check lower half
return binsearch(dictionary,puzzle,low,mid-1);
}
else return 0;
}
char wordSearch(char** dictionary, char** puzzle, int row, int col){
int i, X, Y, dir = 0;
char* wordsfound[20]= {'\0'};
for (X=0;X<row+1;X++){
for(Y=0;Y<col;Y++){
for(dir=0;dir<DX_SIZE;dir++) //check every direction
for(i=0;i<19;i++){
//will continue in direction DX,DY starting at x,y
int nextX = X + DX[dir] * i;
int nextY = Y + DY[dir] * i;
if(nextX < 0 || nextX >= row) break; //keep in bounds
if(nextY < 0 || nextY >= col) break;
//store the string of letters
*wordsfound[i] = (puzzle[nextX][nextY]);
if(i>2){ //minimum word is 3
//if the string of letters is actually a word, print
int bin = binsearch(dictionary,wordsfound,1,listlength);
if(bin){
printf("%s\n",wordsfound);
}
}
}
}
}
}
void freeArray(char** array, int rows){
//free arrays
int i;
for(i=0; i<rows; i++){
free(array[i]);
}
free(array);
}
Here:
char* wordsfound[20]= {'\0'};
for (X=0;X<row+1;X++){
for(Y=0;Y<col;Y++){
for(dir=0;dir<DX_SIZE;dir++) //check every direction
for(i=0;i<19;i++){
...
*wordsfound[i] = (puzzle[nextX][nextY]);
Should be:
char wordsfound[20]= {'\0'}; /* not 20 pointers! */
for (X=0;X<row+1;X++){
for(Y=0;Y<col;Y++){
for(dir=0;dir<DX_SIZE;dir++) //check every direction
for(i=0;i<19;i++){
...
wordsfound[i] = (puzzle[nextX][nextY]); /* no '*' */
wordsfound[i+1] = '\0'; /* end the string */
Also, in your binsearch function when you go to check the upper half or the lower half, you need to make sure that mid+1 and mid-1 respectively are still valid indexes into the array. If you access elements that are outside the array bounds, bad things are waiting to bite you.
For example, if low = 0 and high = 1:
mid = (low+high)/2 ; /* this is zero */
so you compare with the array element 0 and decide you need to look in the lower half, now you call with low as mid-1 which is -1. Oh noes!