Update FourSum.java

Submission Result: Compile Error

Line 19: int cannot be dereferenced

Submission Result: Time Limit Exceeded

Last executed input:	[-497,-481,-481,-472,-471,-465,-422,-420,-413,-405,-388,-381,-366,-361,-359,-348,-334,-334,-318,-310,-305,-280,-273,-272,-262,-254,-248,-223,-208,-202,-196,-192,-189,-167,-165,-165,-156,-143,-136,-122,-120,-120,-108,-77,-50,-44,-34,-26,-17,-5,13,46,46,53,54,56,66,71,72,75,89,115,130,139,149,151,154,196,209,219,230,240,245,246,253,267,277,289,299,302,303,304,342,349,360,361,361,375,392,400,407,408,408,426,427,429,443,451,481], -5617