Find shortest path for rat in the maze allowed to break a wall using backtracking and recursion. What is wrong in my code?

Question

This is a code for finding shortest path through a rectangular (can be square too) maze in which movements in all four directions are allowed and the rat can skip or break one wall. I have used recursion and backtracking below. Out of 5 test cases it is passes 3 of then and wrong answere in the rest. Can any one help me in finding out the mistake...??

def is_safe(m,i,j,a,v):
    if(v[i][j]==False ):
        if(m[i][j]==0):
            return True

        elif(m[i][j]==1 and a[0]==0):
            a[0]+=1
            return True
        elif(m[i][j]==1 and a[0]==1):
            a[0]+=1
            return False
        else:
            return False
    else:
        return False


def solution(m):
    h=len(m)
    w=len(m[0])
    print(h,w)
    v=[]
    for x in range(h):
        a=[]
        for y in range(w):
            a.append(False)
        v.append(a)
    li=[]
    c=0
    p=1
    i=0
    j=0
    path_finder(m,i,j,h,w,li,p,c,v)
    return min(li)

def path_finder(m,i,j,h,w,li,p,c,v):
    if(c==2):
       return
    if(i==h-1 and j==w-1):
        li.append(p)
        return
    a1=[c]
    a2=[c]
    a3=[c]
    a4=[c]

    v[i][j]=True
    if(i+1<h and is_safe(m,i+1,j,a1,v)):
        path_finder(m,i+1,j,h,w,li,p+1,a1[0],v)

    if(i-1>=0 and is_safe(m,i-1,j,a2,v)):
        path_finder(m,i-1,j,h,w,li,p+1,a2[0],v)

    if(j+1<w and is_safe(m,i,j+1,a3,v)):
        path_finder(m,i,j+1,h,w,li,p+1,a3[0],v)

    if(j-1>=0 and is_safe(m,i,j-1,a4,v)):
        path_finder(m,i,j-1,h,w,li,p+1,a4[0],v)

    v[i][j]=False