[solution] check is posible to make triangle

lib/isTriangle.ts

@@ -0,0 +1,14 @@
+export function isTriangle(a: number, b: number, c: number): boolean {
+  if (a < 0 || b < 0 || c < 0) return false;
+
+  return a + b > c && a < b + c && b < a + c;
+}
+
+console.log(isTriangle(7, 2, 2), false);
+console.log(isTriangle(1, 2, 2), true);
+console.log(isTriangle(4, 2, 3), true);
+console.log(isTriangle(2, 2, 2), true);
+console.log(isTriangle(1, 2, 3), false);
+console.log(isTriangle(-5, 1, 3), false);
+console.log(isTriangle(0, 2, 3), false);
+console.log(isTriangle(1, 2, 9), false);