in JavaScript implementation

Produce the output [`Baltimore', `Ravens', `stadium', `is', `located', `Down- town', `near', `Morgan State'].

Using these 4 arrays:

var w = ["Ravens", "stadium", "is", "Orioles", "stadium"]; var x = ["Baltimore", "Downtown", "located", "near"]; var y = ["located", "Downtown", "near", "Fells Point", "Fed Hill", "Canton"]; var z = ["Towson", "Stevenson", "UMBC", "University", "Loyola", "University", "Morgan State", "Frostburg"]; var arr = [];

Can only use push(), pop(), and concat()

In some way must use all four arrays to form "arr"

You cannot create any temp variables, only "arr" - the reuse of variables is fine You can only use push() ONCE You cannot push() array subscripts or String literals. i.e. both arr.push(y[1]) and arr.push("Downtown") are illegal.