If \(f\left( x \right) = \left\{ {\begin{array}{*{20}{c}} {1 + x}&{\text{if}\;x < 0}\\ {\left( {1 - x} \right)\left( {px + q} \right)}&{\text{if}\;x \ge 0} \end{array}} \right.\)

Satisfy the assumption of Rolle’s theorem in the interval [-1, 1], then the sum of (p + q) is