add no.3340

Author: clingoram

javascript/LeetCode/String/3340.js

@@ -0,0 +1,23 @@
+/**
+ * 3340. Check Balanced String
+ * 
+ * 參數為字串數字，檢查index 偶數和基數各自相加後是否相等。
+ * 
+ * @param {string} num
+ * @return {boolean}
+ */
+var isBalanced = function(num) {
+    // solution 
+    // TC:O(N)
+    let oddSum = 0, evenSum = 0;
+    for(let i = 0;i < num.length;++i) {
+        if(i % 2 === 0){
+            evenSum += parseInt(num[i]);
+        }else{
+            oddSum += parseInt(num[i]);
+        }
+    }
+    return evenSum === oddSum;
+};
+let num = "1234";
+console.log(isBalanced(num));