diff --git a/README.md b/README.md
index a90ef380..dec7d1de 100644
--- a/README.md
+++ b/README.md
@@ -718,4 +718,5 @@ LeetCode
 |1420|[Build Array Where You Can Find The Maximum Exactly K Comparisons](https://leetcode.com/problems/build-array-where-you-can-find-the-maximum-exactly-k-comparisons/)|c|[c++](./src/1420-Build-Array-Where-You-Can-Find-The-Maximum-Exactly-K-Comparisons/1420.cpp)|[python](./src/1420-Build-Array-Where-You-Can-Find-The-Maximum-Exactly-K-Comparisons/1420.py)|[go](./src/1420-Build-Array-Where-You-Can-Find-The-Maximum-Exactly-K-Comparisons/1420.go)|[js](./src/1420-Build-Array-Where-You-Can-Find-The-Maximum-Exactly-K-Comparisons/1420.js)|[java](./src/1420-Build-Array-Where-You-Can-Find-The-Maximum-Exactly-K-Comparisons/1420.java)|Hard|
 |1422|[Maximum Score After Splitting a String](https://leetcode.com/problems/maximum-score-after-splitting-a-string/)|c|[c++](./src/1422-Maximum-Score-After-Splitting-a-String/1422.cpp)|[python](./src/1422-Maximum-Score-After-Splitting-a-String/1422.py)|[go](./src/1422-Maximum-Score-After-Splitting-a-String/1422.go)|[js](./src/1422-Maximum-Score-After-Splitting-a-String/1422.js)|[java](./src/1422-Maximum-Score-After-Splitting-a-String/1422.java)|Easy|
 |1423|[Maximum Points You Can Obtain from Cards](https://leetcode.com/problems/maximum-points-you-can-obtain-from-cards/)|c|[c++](./src/1423-Maximum-Points-You-Can-Obtain-from-Cards/1423.cpp)|[python](./src/1423-Maximum-Points-You-Can-Obtain-from-Cards/1423.py)|[go](./src/1423-Maximum-Points-You-Can-Obtain-from-Cards/1423.go)|[js](./src/1423-Maximum-Points-You-Can-Obtain-from-Cards/1423.js)|[java](./src/1423-Maximum-Points-You-Can-Obtain-from-Cards/1423.java)|Medium|
-|1424|[Diagonal Traverse II](https://leetcode.com/problems/diagonal-traverse-ii/)|c|[c++](./src/1424-Diagonal-Traverse-II/1424.cpp)|[python](./src/1424-Diagonal-Traverse-II/1424.py)|[go](./src/1424-Diagonal-Traverse-II/1424.go)|[js](./src/1424-Diagonal-Traverse-II/1424.js)|[java](./src/1424-Diagonal-Traverse-II/1424.java)|Medium|
\ No newline at end of file
+|1424|[Diagonal Traverse II](https://leetcode.com/problems/diagonal-traverse-ii/)|c|[c++](./src/1424-Diagonal-Traverse-II/1424.cpp)|[python](./src/1424-Diagonal-Traverse-II/1424.py)|[go](./src/1424-Diagonal-Traverse-II/1424.go)|[js](./src/1424-Diagonal-Traverse-II/1424.js)|[java](./src/1424-Diagonal-Traverse-II/1424.java)|Medium|
+|1425|[Constrained Subsequence Sum](https://leetcode.com/problems/constrained-subsequence-sum/)|c|[c++](./src/1425-Constrained-Subsequence-Sum/1425.cpp)|[python](./src/1425-Constrained-Subsequence-Sum/1425.py)|[go](./src/1425-Constrained-Subsequence-Sum/1425.go)|[js](./src/1425-Constrained-Subsequence-Sum/1425.js)|[java](./src/1425-Constrained-Subsequence-Sum/1425.java)|Hard|
\ No newline at end of file
diff --git a/src/1425-Constrained-Subsequence-Sum/1425.cpp b/src/1425-Constrained-Subsequence-Sum/1425.cpp
new file mode 100644
index 00000000..468fd933
--- /dev/null
+++ b/src/1425-Constrained-Subsequence-Sum/1425.cpp
@@ -0,0 +1,17 @@
+class Solution {
+public:
+    int constrainedSubsetSum(vector<int>& nums, int k) {
+        deque<int> q;
+        int res = -10000, n = nums.size();
+
+        for (int i = 0; i < n; i++) {
+            nums[i] = max(nums[i], nums[i] + (q.size() ? q.front() : 0));
+            while (q.size() && nums[i] > q.back()) q.pop_back();
+            q.emplace_back(nums[i]);
+
+            if (i >= k && q.size() && q.front() == nums[i - k]) q.pop_front();
+            res = max(res, nums[i]);
+        }
+        return res;
+    }
+};
\ No newline at end of file
diff --git a/src/1425-Constrained-Subsequence-Sum/1425.go b/src/1425-Constrained-Subsequence-Sum/1425.go
new file mode 100644
index 00000000..df4e26ff
--- /dev/null
+++ b/src/1425-Constrained-Subsequence-Sum/1425.go
@@ -0,0 +1,27 @@
+func constrainedSubsetSum(nums []int, k int) int {
+    q := []int{}
+    res, n := -10000, len(nums)
+
+    for i := 0; i < n; i++ {
+        if len(q) > 0 && q[0] > 0 {
+            nums[i] += q[0]
+        }
+        for len(q) > 0 && nums[i] > q[len(q) - 1] {
+            q = q[:len(q) - 1]
+        }
+        q = append(q, nums[i])
+        
+        if i >= k && len(q) > 0 && q[0] == nums[i - k] {
+            q = q[1:]
+        }
+        res = max(res, nums[i])
+    }
+    return res
+}
+
+func max(a, b int) int {
+    if a > b {
+        return a
+    }
+    return b
+}
\ No newline at end of file
diff --git a/src/1425-Constrained-Subsequence-Sum/1425.java b/src/1425-Constrained-Subsequence-Sum/1425.java
new file mode 100644
index 00000000..7c0c2b65
--- /dev/null
+++ b/src/1425-Constrained-Subsequence-Sum/1425.java
@@ -0,0 +1,16 @@
+class Solution {
+    public int constrainedSubsetSum(int[] nums, int k) {
+        Deque<Integer> q = new ArrayDeque();
+        int res = -10000, n = nums.length;
+
+        for (int i = 0; i < n; i++) {
+            nums[i] = Math.max(nums[i], nums[i] + (q.isEmpty() ? 0 : q.peek()));
+            while (!q.isEmpty() && nums[i] > q.peekLast()) q.pollLast();
+            q.offer(nums[i]);
+
+            if (i >= k && !q.isEmpty() && q.peek() == nums[i - k]) q.poll();
+            res = Math.max(res, nums[i]);
+        }
+        return res;
+    }
+}
\ No newline at end of file
diff --git a/src/1425-Constrained-Subsequence-Sum/1425.js b/src/1425-Constrained-Subsequence-Sum/1425.js
new file mode 100644
index 00000000..60c24920
--- /dev/null
+++ b/src/1425-Constrained-Subsequence-Sum/1425.js
@@ -0,0 +1,13 @@
+var constrainedSubsetSum = function(nums, k) {
+    let q = [], res = -10000, n = nums.length;
+
+    for (let i = 0; i < n; i++) {
+        nums[i] = Math.max(nums[i], nums[i] + (q.length ? q[0] : 0));
+        while (q.length && nums[i] > q[q.length - 1]) q.pop();
+        q.push(nums[i]);
+
+        if (i >= k && q.length && q[0] == nums[i - k]) q.shift();
+        res = Math.max(res, nums[i]);
+    }
+    return res;
+};
\ No newline at end of file
diff --git a/src/1425-Constrained-Subsequence-Sum/1425.py b/src/1425-Constrained-Subsequence-Sum/1425.py
new file mode 100644
index 00000000..72974715
--- /dev/null
+++ b/src/1425-Constrained-Subsequence-Sum/1425.py
@@ -0,0 +1,13 @@
+class Solution:
+    def constrainedSubsetSum(self, nums: List[int], k: int) -> int:
+        q, res = [], float("-inf")
+        for i, v in enumerate(nums):
+            nums[i] = max(v, v + (q[0] if q else 0))
+            while q and nums[i] > q[-1]:
+                q.pop()
+            q.append(nums[i]) 
+
+            if i >= k and q and q[0] == nums[i - k]:
+                q.pop(0)
+            res = max(res, nums[i])
+        return res
\ No newline at end of file
diff --git a/src/addProb.py b/src/addProb.py
index fc469a0d..cb075056 100644
--- a/src/addProb.py
+++ b/src/addProb.py
@@ -2,10 +2,10 @@
 import os, bisect
 
 # 题目名称
-name = "Diagonal Traverse II"
-ID = 1424
-url = "https://leetcode.com/problems/diagonal-traverse-ii/"
-difficult = "Medium"
+name = "Constrained Subsequence Sum"
+ID = 1425
+url = "https://leetcode.com/problems/constrained-subsequence-sum/"
+difficult = "Hard"
 prog = ['c', 'cpp', 'py', 'go', 'js', 'java']