From 12bf8ae05b176816a21cfd741b2274bfada14aae Mon Sep 17 00:00:00 2001
From: Steve2020 <841532108@qq.com>
Date: Fri, 14 Jan 2022 22:36:55 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=EF=BC=880018.=E5=9B=9B?=
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 =?UTF-8?q?=E5=8A=A0typescript=E7=89=88=E6=9C=AC?=
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---
 problems/0018.四数之和.md | 42 +++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/problems/0018.四数之和.md b/problems/0018.四数之和.md
index b94ebeef..dae8636b 100644
--- a/problems/0018.四数之和.md
+++ b/problems/0018.四数之和.md
@@ -311,7 +311,49 @@ var fourSum = function(nums, target) {
 };
 ```
 
+TypeScript：
+
+```typescript
+function fourSum(nums: number[], target: number): number[][] {
+    nums.sort((a, b) => a - b);
+    let first: number = 0,
+        second: number,
+        third: number,
+        fourth: number;
+    let length: number = nums.length;
+    let resArr: number[][] = [];
+    for (; first < length; first++) {
+        if (first > 0 && nums[first] === nums[first - 1]) {
+            continue;
+        }
+        for (second = first + 1; second < length; second++) {
+            if ((second - first) > 1 && nums[second] === nums[second - 1]) {
+                continue;
+            }
+            third = second + 1;
+            fourth = length - 1;
+            while (third < fourth) {
+                let total: number = nums[first] + nums[second] + nums[third] + nums[fourth];
+                if (total === target) {
+                    resArr.push([nums[first], nums[second], nums[third], nums[fourth]]);
+                    third++;
+                    fourth--;
+                    while (nums[third] === nums[third - 1]) third++;
+                    while (nums[fourth] === nums[fourth + 1]) fourth--;
+                } else if (total < target) {
+                    third++;
+                } else {
+                    fourth--;
+                }
+            }
+        }
+    }
+    return resArr;
+};
+```
+
 PHP:
+
 ```php
 class Solution {
     /**