generateMatrix.py

class Solution:
    # @param A : integer
    # @return a list of list of integers
    def generateMatrix(self, A):
        n = A
        ret = [[0]*n]
        for i in range(n-1):
	        ret.append([0]*n)

        T = 0
        B = n-1
        L = 0
        R = n-1
        direction = 0
        num = 1
        while T <=B and L <=R:
        	if direction == 0:
        		for i in range(L,R+1):
        			ret[T][i] = num
        			num += 1
                    T += 1
        		    direction = 1
        	elif direction == 1:
        		for i in range(T,B+1):
        			ret[i][R] = num
        			num += 1
        		    R -= 1
        		    direction = 2
        	elif direction == 2:
        		for i in range(R,L-1,-1):
        			ret[B][i] = num
        			num += 1
        		    B -= 1
        		    direction = 3
        	else:
        		for i in range(B,T-1,-1):
        			ret[i][L] = num
        			num += 1
        		    L += 1
        		    direction = 0
        return ret