Searching a particular word in a matrix of characters - c

Question

I was trying to search for a particular word in a matrix of characters through C but was unable to come to a fixed solution.
For ex:
Suppose I have to search for the word INTELLIGENT in a matrix of characters (3*9)
(Once you have picked a character from the matrix to form a sentence, you cannot pick it again to form the same sentence.There is a path from any cell to all its neighboring cells. A neighbor may share an edge or a corner.)
IIIINN.LI
....TTEGL
.....NELI
Output: YES (the word INTELLIGENT can be found)
Can anybody please give a solution to the above problem !!!!

Answer 1

Use a depth first search.
You can do this using a recursive algorthm. Find all the (unused) places containing the first letter then see if it is possible to find the rest of the word on the remaining board by starting from one of the adjacent squares.

Answer 2

#include <stdio.h>
char Matrix[3][9] = {
{ 'I','I','I','I','N','N','.','L','I'},
{ '.','.','.','.','T','T','E','G','L'},
{ '.','.','.','.',',','N','E','L','I'}
};
char Choice[3][9] = { { 0 }, { 0 }, { 0 } };
const char WORD[] = "INTELLIGENT";
const int Len = sizeof(WORD)-1;
int Path[sizeof(WORD)-1] = { 0 };
char get(int row, int col){
if(1 > col || col > 9) return '\0';
if(1 > row || row > 3) return '\0';
if(Choice[row-1][col-1] || Matrix[row-1][col-1] == '.')
return '\0';
else
return Matrix[row-1][col-1];
}
#define toLoc(r, c) (r)*10+(c)
#define getRow(L) L/10
#define getCol(L) L%10
int search(int loc, int level){
int r,c,x,y;
char ch;
if(level == Len) return 1;//find it
r = getRow(loc);
c = getCol(loc);
ch = get(r,c);
if(ch == 0 || ch != WORD[level]) return 0;
Path[level]=toLoc(r,c);
Choice[r-1][c-1] = 'v';//marking
for(x=-1;x<=1;++x){
for(y=-1;y<=1;++y){
if(search(toLoc(r+y,c+x), level + 1)) return 1;
}
}
Choice[r-1][c-1] = '\0';//reset
return 0;
}
int main(void){
int r,c,i;
for(r=1;r<=3;++r){
for(c=1;c<=9;++c){
if(search(toLoc(r,c), 0)){
printf("YES\nPath:");
for(i=0;i<Len;++i){
printf("(%d,%d)", getRow(Path[i]), getCol(Path[i]));
}
printf("\n");
return 0;
}
}
}
printf("NO\n");
return 0;
}

Answer 3

I think this is what you mean..... Though it seems simpler to what you currently have been offered, so I may have misunderstood the question.
I use Numpy to reshape an arbitrary array into a single
list of letters, then we create a mask of the search term and
a copy of the input list.
I tick off each letter to search for while updating the mask.
import numpy as np
import copy
def findInArray(I,Word):
M=[list(x) for x in I]
M=list(np.ravel(M))
print "Letters to start: %s"%"".join(M)
Mask=[False]*len(Word)
T = copy.copy(M)
for n,v in enumerate(Word):
try:
p=T.index(v)
except ValueError:
pass
else:
T[p]=''
Mask[n]=True
print "Letters left over: %s"%"".join(T)
if all(Mask):print "Found %s"%Word
else:print "%s not Found"%Word
print "\n"
return all(Mask)
I=["IIIINN.LI","....TTEGL",".....NELI"]
findInArray(I,"INTEL")
findInArray(I,"INTELLIGENT")
findInArray(I,"INTELLIGENCE")
Example output
Letters to start: IIIINN.LI....TTEGL.....NELI
Letters left over: IIIN.I....TGL.....NELI
Found INTEL
Letters to start: IIIINN.LI....TTEGL.....NELI
Letters left over: II.I.........NLI
Found INTELLIGENT
Letters to start: IIIINN.LI....TTEGL.....NELI
Letters left over: II.I....T.....NLI
INTELLIGENCE not Found

Answer 4

#include <stdio.h>
#define ROW 1
#define COL 11
char Matrix[ROW][COL] = { { 'I','N','T','E','L','L','I','G','E', 'N', 'T'} };
char Choice[ROW][COL] = { { 0 } };
const char WORD[] = "INTELLIGENT";
const int Len = sizeof(WORD)-1;
int Path[sizeof(WORD)-1] = { 0 };
char get(int row, int col){
if(1 > col || col > COL) return '\0';
if(1 > row || row > ROW) return '\0';
if(Choice[row-1][col-1] || Matrix[row-1][col-1] == '.')
return '\0';
else
return Matrix[row-1][col-1];
}
#define toLoc(r, c) (r)*16+(c)
#define getRow(L) L/16
#define getCol(L) L%16
int search(int loc, int level){
int r,c,x,y;
char ch;
if(level == Len) return 1;//find it
r = getRow(loc);
c = getCol(loc);
ch = get(r,c);
if(ch == 0 || ch != WORD[level]) return 0;
Path[level]=toLoc(r,c);
Choice[r-1][c-1] = 'v';//marking
for(x=-1;x<=1;++x){
for(y=-1;y<=1;++y){
if(search(toLoc(r+y,c+x), level + 1)) return 1;
}
}
Choice[r-1][c-1] = '\0';//reset
return 0;
}
int main(void){
int r,c,i;
for(r=1;r<=ROW;++r){
for(c=1;c<=COL;++c){
if(search(toLoc(r,c), 0)){
printf("YES\nPath:");
for(i=0;i<Len;++i){
printf("(%d,%d)", getRow(Path[i]), getCol(Path[i]));
}
printf("\n");
return 0;
}
}
}
printf("NO\n");
return 0;
}