383. 赎金信

Author: w2xi

README.md

@@ -78,6 +78,7 @@
 |344|[反转字符串](https://leetcode-cn.com/problems/reverse-string/)|[JavaScript](./algorithms/reverse-string.js)|Easy|
 |349|[两个数组的交集](https://leetcode-cn.com/problems/intersection-of-two-arrays/)|[JavaScript](./algorithms/intersection-of-two-arrays.js)|Easy|
 |350|[两个数组的交集 II](https://leetcode-cn.com/problems/intersection-of-two-arrays-ii/)|[JavaScript](./algorithms/intersection-of-two-arrays-ii.js)|Easy|
+|383|[赎金信](https://leetcode.cn/problems/ransom-note/)|[JavaScript](./algorithms/ransom-note.js)|Easy|
 |387|[字符串中的第一个唯一字符](https://leetcode-cn.com/problems/first-unique-character-in-a-string/)|[JavaScript](./algorithms/first-unique-character-in-a-string.js)|Easy|
 |389|[找不同](https://leetcode.cn/problems/find-the-difference/)|[JavaScript](./algorithms/find-the-difference.js)|Easy|
 |396|[旋转函数](https://leetcode.cn/problems/rotate-function/)|[JavaScript](./algorithms/rotate-function.js)|Medium|

algorithms/ransom-note.js

@@ -0,0 +1,52 @@
+/**
+ * @param {string} ransomNote
+ * @param {string} magazine
+ * @return {boolean}
+ */
+var canConstruct = function (ransomNote, magazine) {
+  // 数组哈希计数
+  const countArr = Array(26).fill(0);
+
+  for (let char of magazine) {
+    const index = char.charCodeAt() - "a".charCodeAt();
+    countArr[index]++;
+  }
+
+  for (let char of ransomNote) {
+    const index = char.charCodeAt() - "a".charCodeAt();
+    countArr[index]--;
+
+    if (countArr[index] < 0) {
+      return false;
+    }
+  }
+
+  return true;
+
+  // 哈希表
+  // const map = new Map();
+
+  // for (let char of magazine) {
+  //   if (map.has(char)) {
+  //     const count = map.get(char);
+  //     map.set(char, count + 1);
+  //   } else {
+  //     map.set(char, 1);
+  //   }
+  // }
+
+  // for (let char of ransomNote) {
+  //   if (map.has(char)) {
+  //     const count = map.get(char);
+  //     if (count - 1 < 0) {
+  //       return false;
+  //     } else {
+  //       map.set(char, count - 1);
+  //     }
+  //   } else {
+  //     return false;
+  //   }
+  // }
+
+  // return true;
+};