feat: add javascript solution to lc problem: No.1880.Check if Word Equals Summation of Two Words (doocs#419)

Author: zhaocchen

solution/1800-1899/1880.Check if Word Equals Summation of Two Words/README.md

@@ -124,6 +124,35 @@ private:
 };
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {string} firstWord
+ * @param {string} secondWord
+ * @param {string} targetWord
+ * @return {boolean}
+ */
+ var isSumEqual = function(firstWord, secondWord, targetWord) {
+    let carry = 0;
+    let n1 = firstWord.length, n2 = secondWord.length;
+    let n3 = targetWord.length;
+    for (let i = 0; i < n3; i++) {
+        let num1 = getNum(firstWord.charAt(n1 - 1 - i));
+        let num2 = getNum(secondWord.charAt(n2 - 1 - i));
+        let sum = carry + num1 + num2;
+        if (getNum(targetWord.charAt(n3 - 1 - i)) != (sum % 10)) return false;
+        carry = parseInt(sum / 10);
+    }
+    return true;
+};
+
+function getNum (char) {
+    if (!char) return 0;
+    return char.charCodeAt() - 'a'.charCodeAt();
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1880.Check if Word Equals Summation of Two Words/README_EN.md

@@ -144,6 +144,35 @@ private:
 };
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {string} firstWord
+ * @param {string} secondWord
+ * @param {string} targetWord
+ * @return {boolean}
+ */
+ var isSumEqual = function(firstWord, secondWord, targetWord) {
+    let carry = 0;
+    let n1 = firstWord.length, n2 = secondWord.length;
+    let n3 = targetWord.length;
+    for (let i = 0; i < n3; i++) {
+        let num1 = getNum(firstWord.charAt(n1 - 1 - i));
+        let num2 = getNum(secondWord.charAt(n2 - 1 - i));
+        let sum = carry + num1 + num2;
+        if (getNum(targetWord.charAt(n3 - 1 - i)) != (sum % 10)) return false;
+        carry = parseInt(sum / 10);
+    }
+    return true;
+};
+
+function getNum (char) {
+    if (!char) return 0;
+    return char.charCodeAt() - 'a'.charCodeAt();
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1880.Check if Word Equals Summation of Two Words/Solution.js

@@ -0,0 +1,24 @@
+/**
+ * @param {string} firstWord
+ * @param {string} secondWord
+ * @param {string} targetWord
+ * @return {boolean}
+ */
+ var isSumEqual = function(firstWord, secondWord, targetWord) {
+    let carry = 0;
+    let n1 = firstWord.length, n2 = secondWord.length;
+    let n3 = targetWord.length;
+    for (let i = 0; i < n3; i++) {
+        let num1 = getNum(firstWord.charAt(n1 - 1 - i));
+        let num2 = getNum(secondWord.charAt(n2 - 1 - i));
+        let sum = carry + num1 + num2;
+        if (getNum(targetWord.charAt(n3 - 1 - i)) != (sum % 10)) return false;
+        carry = parseInt(sum / 10);
+    }
+    return true;
+};
+
+function getNum (char) {
+    if (!char) return 0;
+    return char.charCodeAt() - 'a'.charCodeAt();
+}