Another alternative: use RLE (run-length-estimation), borrowed originally from a very simple data compressor of the same name.

Here's the code, albeit in the R language. (For non-users, 1L just forces integer-class, x[-k] means all of vector x except index 'k' )

Here's the base package code for the function rle(x) :
First line: generate logical vector of "is x[j] == x[j-1] ? "

  y <- x[-1L] != x[-n] ;

which returns index values when argument is TRUE, and c concatenates vectors (is.na just catches N/A values in case the input was skeevy)

 i <- c(which(y | is.na(y)), n) ; 

finally, create a structure. First element calculates run lengths by comparing sequential index values in i ; second element returns the value of the input vector every time that run terminates

  structure(list(lengths = diff(c(0L, i)), values = x[i]), class = "rle")

then add a line to find max(lengths[values==0]).

Another alternative: use RLE (run-length-encoding; with thanks to the comments for the correct naming), borrowed originally from a very simple data compressor of the same name.

Here's the code, albeit in the R language. (For non-users, 1L just forces integer-class, x[-k] means all of vector x except index 'k' )

Here's the base package code for the function rle(x) :
First line: generate logical vector of "is x[j] == x[j-1] ? "

  y <- x[-1L] != x[-n] ;

which returns index values when argument is TRUE, and c concatenates vectors (is.na just catches N/A values in case the input was skeevy)

 i <- c(which(y | is.na(y)), n) ; 

finally, create a structure. First element calculates run lengths by comparing sequential index values in i ; second element returns the value of the input vector every time that run terminates

  structure(list(lengths = diff(c(0L, i)), values = x[i]), class = "rle")

then add a line to find max(lengths[values==0]).

Another alternative: use RLE (run-length-estimation), borrowed originally from a very simple data compressor of the same name.

Here's the code, albeit in the R language. (For non-users, "1L" just forces integer-class, x[-k] means all of vector x except index 'k' )

Here's the base package code for the function rle(x) :

y <- x[-1L] != x[-n] ; 
i <- c(which(y | is.na(y)), n) ; 
structure(list(lengths = diff(c(0L, i)), values = x[i]), class = "rle") 

then add a line to find max(lengths[values==0])

Another alternative: use RLE (run-length-estimation), borrowed originally from a very simple data compressor of the same name.

Here's the code, albeit in the R language. (For non-users, 1L just forces integer-class, x[-k] means all of vector x except index 'k' )

Here's the base package code for the function rle(x) :
First line: generate logical vector of "is x[j] == x[j-1] ? "

  y <- x[-1L] != x[-n] ;

which returns index values when argument is TRUE, and c concatenates vectors (is.na just catches N/A values in case the input was skeevy)

 i <- c(which(y | is.na(y)), n) ; 

finally, create a structure. First element calculates run lengths by comparing sequential index values in i ; second element returns the value of the input vector every time that run terminates

  structure(list(lengths = diff(c(0L, i)), values = x[i]), class = "rle")

then add a line to find max(lengths[values==0]).