Update find-array-given-subset-sums.cpp

Author: kamyu104

C++/find-array-given-subset-sums.cpp

@@ -2,7 +2,7 @@
 // Space: O(1)
 
 // [proof]
-// - let d = sorted_sums[0]-sorted_sums[1] and d != -d, where one of +d/-d is the smallest positive or largest negative number of the original solution of [S1, ..., S(2^n)]
+// - let d = sorted_sums[0]-sorted_sums[1] and d != -d (d = 0 is trival), where one of +d/-d is the smallest positive or largest negative number of the original solution of [S1, ..., S(2^n)]
 // - given Sp-d = 0 for some p in [1, 2^n] and Sq-(-d) = 0 for some q in [1, 2^n]
 //   assume d is a number of the original solution of [S1, ..., S(2^n)] (the proof where -d is a number of the original solution is vice versa)
 //   let Sq = x1+...+xi where 1 <= i <= n-1