Buggy python submission (verdict: Time Limit Exceeded):
MAX = 10**9 + 7

def solve():
    N = int(raw_input())
    arr = [int(_) for _ in raw_input().split()]
    xor_acu = [0] * (N + 1)
    for i in range(1, N + 1):
        xor_acu[i] = xor_acu[i - 1] ^ arr[i - 1]
    if xor_acu[N] != 0: # search for 0, X, 0, X ..., 0, X type
        X = xor_acu[N]
        dp0 = [1] * (N + 1)
        dpX = [0] * (N + 1)
        for i in range(1,N+1):
            dp0[i] = dp0[i-1] + dpX[i-1] if xor_acu[i] == 0 else dp0[i - 1]
            dpX[i] = dp0[i-1] + dpX[i-1] if xor_acu[i] == X else dpX[i - 1]
        ret = dp0[N - 1]
    else: # search for 0, X, 0, X ..., X, 0 type
        # X == 0 case
        tmp = 1
        Not0Set = set()
        for i in range(1, N):
            if xor_acu[i] == 0:
                tmp *= 2
            else:
                Not0Set.add(xor_acu[i])
        ret = tmp
        if ret > MAX:
            ret = ret % MAX
        # X != 0 case
        for X in list(Not0Set):
            RLE = [] # Run Length Encoding
            _tmp = xor_acu[0]
            cnt = 1
            all_cnt = 1
            for i in range (1, N+1):
                if xor_acu[i] == 0 or xor_acu[i] == X:
                    if xor_acu[i] == _tmp:
                        cnt += 1
                    else:
                        RLE.append((_tmp, cnt))
                        _tmp = xor_acu[i]
                        cnt = 1
                    all_cnt += 1
            RLE.append((_tmp, cnt))
            lRLE = all_cnt
            Not0dp0 = [1] * lRLE
            Not0dpX = [0] * lRLE
            ind = 1
            for i in range(len(RLE)):
                start = 1 if i == 0 else 0
                if RLE[i][0] == 0:
                    for j in range(start, RLE[i][1]):
                        Not0dp0[ind] = Not0dp0[ind - 1] + Not0dpX[ind - 1]
                        Not0dpX[ind] = Not0dpX[ind - 1]
                        ind += 1
                else:
                    for j in range(start, RLE[i][1]):
                        Not0dp0[ind] = Not0dp0[ind - 1]
                        Not0dpX[ind] = Not0dp0[ind - 1] + Not0dpX[ind - 1]
                        ind += 1
            ret += Not0dpX[ind - 2]
            if ret > MAX:
                ret = ret % MAX
    print str(ret)

if __name__ == '__main__':
    solve()


Fixed submission:
MAX = 10**9 + 7
MAXAi = 1<<20

def solve2():
    N = int(raw_input())
    arr = [int(_) for _ in raw_input().split()]
    xor_acu = [0] * (N + 1)
    for i in range(1, N + 1):
        xor_acu[i] = xor_acu[i - 1] ^ arr[i - 1]
    dp = [[not j for i in range(MAXAi)] for j in range(2)]
    cnt = [0 for i in range (MAXAi)]
    cnt_zero = 0
    for i in range(1, N + 1):
        if xor_acu[i] == 0:
            cnt_zero += 1
        dp[0][xor_acu[i]] += dp[1][xor_acu[i]] * (cnt_zero - cnt[xor_acu[i]])
        dp[0][xor_acu[i]] %= MAX
        dp[1][xor_acu[i]] += dp[0][xor_acu[i]]
        dp[1][xor_acu[i]] %= MAX
        cnt[xor_acu[i]] = cnt_zero
    if xor_acu[N] != 0:
        ret = dp[0][xor_acu[N]]
    else:
        ret = pow(2, cnt_zero - 1, MAX)
        for j in range(1, MAXAi):
            ret += dp[1][j]
            ret %= MAX
    print str(ret)

if __name__ == '__main__':
    solve2()

Buggy python submission (verdict: Time Limit Exceeded):
MAX = 10**9 + 7

def solve():
    N = int(raw_input())
    arr = [int(_) for _ in raw_input().split()]
    xor_acu = [0] * (N + 1)
    for i in range(1, N + 1):
        xor_acu[i] = xor_acu[i - 1] ^ arr[i - 1]
    if xor_acu[N] != 0: # search for 0, X, 0, X ..., 0, X type
        X = xor_acu[N]
        dp0 = [1] * (N + 1)
        dpX = [0] * (N + 1)
        for i in range(1,N+1):
            dp0[i] = dp0[i-1] + dpX[i-1] if xor_acu[i] == 0 else dp0[i - 1]
            dpX[i] = dp0[i-1] + dpX[i-1] if xor_acu[i] == X else dpX[i - 1]
        ret = dp0[N - 1]
    else: # search for 0, X, 0, X ..., X, 0 type
        # X == 0 case
        tmp = 1
        Not0Set = set()
        for i in range(1, N):
            if xor_acu[i] == 0:
                tmp *= 2
            else:
                Not0Set.add(xor_acu[i])
        ret = tmp
        if ret > MAX:
            ret = ret % MAX
        # X != 0 case
        for X in list(Not0Set):
            RLE = [] # Run Length Encoding
            _tmp = xor_acu[0]
            cnt = 1
            all_cnt = 1
            for i in range (1, N+1):
                if xor_acu[i] == 0 or xor_acu[i] == X:
                    if xor_acu[i] == _tmp:
                        cnt += 1
                    else:
                        RLE.append((_tmp, cnt))
                        _tmp = xor_acu[i]
                        cnt = 1
                    all_cnt += 1
            RLE.append((_tmp, cnt))
            lRLE = all_cnt
            Not0dp0 = [1] * lRLE
            Not0dpX = [0] * lRLE
            ind = 1
            for i in range(len(RLE)):
                start = 1 if i == 0 else 0
                if RLE[i][0] == 0:
                    for j in range(start, RLE[i][1]):
                        Not0dp0[ind] = Not0dp0[ind - 1] + Not0dpX[ind - 1]
                        Not0dpX[ind] = Not0dpX[ind - 1]
                        ind += 1
                else:
                    for j in range(start, RLE[i][1]):
                        Not0dp0[ind] = Not0dp0[ind - 1]
                        Not0dpX[ind] = Not0dp0[ind - 1] + Not0dpX[ind - 1]
                        ind += 1
            ret += Not0dpX[ind - 2]
            if ret > MAX:
                ret = ret % MAX
    print str(ret)

if __name__ == '__main__':
    solve()


Fixed submission:
MAX = 10**9 + 7
MAXAi = 1<<20

def solve2():
    N = int(raw_input())
    arr = [int(_) for _ in raw_input().split()]
    xor_acu = [0] * (N + 1)
    for i in range(1, N + 1):
        xor_acu[i] = xor_acu[i - 1] ^ arr[i - 1]
    dp = [[not j for i in range(MAXAi)] for j in range(2)]
    cnt = [0 for i in range (MAXAi)]
    cnt_zero = 0
    for i in range(1, N + 1):
        if xor_acu[i] == 0:
            cnt_zero += 1
        dp[0][xor_acu[i]] += dp[1][xor_acu[i]] * (cnt_zero - cnt[xor_acu[i]])
        dp[0][xor_acu[i]] %= MAX
        dp[1][xor_acu[i]] += dp[0][xor_acu[i]]
        dp[1][xor_acu[i]] %= MAX
        cnt[xor_acu[i]] = cnt_zero
    if xor_acu[N] != 0:
        ret = dp[0][xor_acu[N]]
    else:
        ret = pow(2, cnt_zero - 1, MAX)
        for j in range(1, MAXAi):
            ret += dp[1][j]
            ret %= MAX
    print str(ret)

if __name__ == '__main__':
    solve2()