Maximums

maxs x    maxs[x]

Where x is a non-symbol sortable list, returns the running maximums of its prefixes.

Nulls are ignored, except that initial nulls are returned as negative infinity.

q)maxs 2 5 7 1 3
2 5 7 7 7
q)maxs "genie"
"ggnnn"
q)maxs 0N 5 0N 1 3         / initial nulls return negative infinity
-0W 5 5 5 5

maxs is a uniform function. It is equivalent to |\.