'''
0:left
1:right
2:up
3:down
'''
paths = []
def path_in_matrix(matrix, s):
row, col = len(matrix), len(matrix[0])
global paths
paths = []
if len(s) == 0:
return True
def go_next(matrix, i, j, s, src):
if len(s) == 0:
return True
if i >= row or j >= col or matrix[i][j] != s[0]:
return False
paths.append((i,j))
if src != 0 and go_next(matrix, i, j-1, s[1:], 1):
return True
if src != 1 and go_next(matrix, i, j+1, s[1:], 0):
return True
if src != 2 and go_next(matrix, i-1, j, s[1:], 3):
return True
if src != 3 and go_next(matrix, i+1, j, s[1:], 2):
return True
paths.pop()
return False
for i in range(row):
for j in range(col):
if matrix[i][j] == s[0]:
paths.append((i,j))
if go_next(matrix, i, j-1, s[1:], 1): #go from right
return True
if go_next(matrix, i, j+1, s[1:], 0): #go from left
return True
if go_next(matrix, i-1, j, s[1:], 3): #go from down
return True
if go_next(matrix, i+1, j, s[1:], 2): #go from up
return True
paths.pop()
return False
if __name__ == "__main__":
matrix = [['a', 'b', 't', 'g'],
['c', 'f', 'c', 's'],
['j', 'd', 'e', 'h'],
]
print(path_in_matrix(matrix, 'bfce'))
print(paths)
print(path_in_matrix(matrix, 'abfb'))
print(paths)
print(path_in_matrix(matrix, 'tceh'))
print(paths)
