diff --git a/0209-Minimum_Size_Subarray_Sum/main.ts b/0209-Minimum_Size_Subarray_Sum/main.ts
new file mode 100644
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+++ b/0209-Minimum_Size_Subarray_Sum/main.ts
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+// let target = 7,
+//   nums = [2, 3, 1, 2, 4, 3];
+// let target = 4,
+//   nums = [1, 4, 4];
+let target = 11,
+  nums = [1, 1, 1, 1, 1, 1, 1, 1];
+
+function miniSubArrayLen(target: number, nums: number[]): number {
+  let left: number = 0,
+    right: number = 0;
+  let res: number = nums.length + 1;
+  let sum: number = 0;
+  while (right < nums.length) {
+    sum += nums[right];
+    if (sum >= target) {
+      while (sum - nums[left] >= target) {
+        sum -= nums[left++];
+      }
+      res = Math.min(res, right - left + 1);
+    }
+    right++;
+  }
+  return res === nums.length + 1 ? 0 : res;
+}
+
+let result = miniSubArrayLen(target, nums);
+console.time("miniSubArrayLen");
+miniSubArrayLen(target, nums);
+console.timeEnd("miniSubArrayLen");
+
+console.log(result);
diff --git a/0209-Minimum_Size_Subarray_Sum/readme.md b/0209-Minimum_Size_Subarray_Sum/readme.md
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+# 209. Minimum Size Subarray Sum
+
+Given an array of positive integers `nums` and a positive integer `target`, return <i>the <b>minimal length</b> of a
+<span style="color: #007ef9;" title="A subarray is a contiguous non-empty sequence of elements within an array.">subarray</span>
+whose sum is greater than or equal to</i> `target`. If there is no such subarray, return `0` instead.
+
+## Example 1:
+
+> <span style="color: white;">Input: </span>target = 7, nums = [2, 3, 1, 2, 4, 3]<br>
+> <span style="color: white;">Output: </span>2<br>
+> <span style="color: white;">Explanation: </span>The subarray [4, 3] has the minimal length under the problem constraint.
+
+## Example 2:
+
+> <span style="color: white;">Input: </span>target = 4, nums = [1, 4, 4]<br>
+> <span style="color: white;">Output: </span>1
+
+## Example 3:
+
+> <span style="color: white;">Input: </span>target = 11, nums = [1, 1, 1, 1, 1, 1, 1, 1]<br>
+> <span style="color: white;">Output: </span>0
+
+### Constraints:
+
+- 1 <= target <= 10<sup>9</sup>
+- 1 <= nums.length <= 10<sup>5</sup>
+- 1 <= nums[i] <= 10<sup>4</sup>