[BUGFIX] Unexpected negated condition.

Negated conditions should be avoided when an else clause is present typescript:S7735

Author: Gonzalo Diaz

src/hackerrank/implementation/migratoryBirds.ts

@@ -17,10 +17,10 @@ function migratoryBirds(arr: number[]): number {
   for (const bird of arr) {
     console.debug(`bird ${bird}`);
 
-    if (!map[bird]) {
-      map[bird] = 1;
-    } else {
+    if (map[bird]) {
       map[bird] += 1;
+    } else {
+      map[bird] = 1;
     }
 
     console.debug(`bird = ${bird} ~> map[bird] = ${map[bird]}`);