Two numbers in an array adding up to a given number

two-numbers-in-an-array-adding-up-to-a-given-number/index.js

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+// https://www.codewars.com/kata/two-numbers-in-an-array-adding-up-to-a-given-number
+
+function hasPair(a, sum) {
+  a.sort((a, b) => a - b);
+  let [li, ui] = [0, a.length -1];
+  while (li < ui) {
+    const tmp = a[li] + a[ui];
+    if (tmp === sum) return true;
+    if (tmp < sum) {
+      ++li;
+    } else {
+      --ui;
+    }
+  }
+  return false;
+}