add 0209 Solution for Java

Author: EndaLin

solution/0200-0299/0209.Minimum Size Subarray Sum/Solution.java

@@ -0,0 +1,20 @@
+class Solution {
+    public int minSubArrayLen(int s, int[] nums) {
+        int n = nums.length;
+        int ans = Integer.MAX_VALUE;
+        int start = 0, end = 0;
+        int sum = 0;
+        while (start < n) {
+            while (end < n && sum < s) {
+                sum += nums[end];
+                end++;
+            }
+            if (sum >= s) {
+                ans = Math.min(ans, end - start);
+            }
+            sum -= nums[start];
+            start++;
+        }
+        return ans == Integer.MAX_VALUE ? 0 : ans;
+    }
+}