Implement NOT operator

src/bigint.rs

@@ -210,6 +210,23 @@ impl Neg for BigInt {
     }
 }
 
+impl Not for BigInt {
+    type Output = Self;
+
+    fn not(self) -> Self::Output {
+        let mut flipped: Vec<usize> = Vec::with_capacity(self.inner.len());
+
+        for (i, val) in self.inner.iter().enumerate() {
+            flipped[i] = val.reverse_bits();
+        }
+
+        BigInt {
+            sign: self.sign,
+            inner: flipped,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -237,6 +254,12 @@ mod tests {
             "least significant place should be MAX - 1"
         );
         assert_eq!(sum.inner[1], 1usize, "most significant place should be 1");
+
+        /* let a = BigInt::from(core::usize::MAX);
+        let b = BigInt::from(1usize);
+        let sum = a + b;
+        assert_eq!(sum.inner[0], 0usize);
+        assert_eq!(sum.inner[1], 1usize); */
     }
 
     #[test]