[황은지] Day15

leetcode3/황은지/374. Guess Number Higher or Lower.js

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+/**
+ * Forward declaration of guess API.
+ * @param {number} num   your guess
+ * @return 	     -1 if num is higher than the picked number
+ *			      1 if num is lower than the picked number
+ *               otherwise return 0
+ * var guess = function(num) {}
+ */
+
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var guessNumber = function (n) {
+  let left = 1;
+  let right = n;
+  while (true) {
+    let mid = Math.floor((left + right) / 2);
+    const result = guess(mid);
+    if (result === -1) {
+      right = mid - 1;
+    } else if (result === 1) {
+      left = mid + 1;
+    } else return mid;
+  }
+};