diff --git a/daily/Sep13.cc b/daily/Sep13.cc
new file mode 100644
index 0000000..9e2c8cd
--- /dev/null
+++ b/daily/Sep13.cc
@@ -0,0 +1,33 @@
+#include <deque>
+#include <iostream>
+using namespace std;
+
+class Solution {
+ public:
+  int maximumRobots(vector<int>& chargeTimes, vector<int>& runningCosts,
+                    long long budget) {
+    int ans = 0, le = 0;
+    long long sum = 0;
+    deque<int> dq;
+    for (int ri = 0; ri < chargeTimes.size(); ri++) {
+      // enque
+      while (!dq.empty() && chargeTimes[ri] >= chargeTimes[dq.back()]) {
+        dq.pop_back();
+      }
+      dq.push_back(ri);
+      sum += runningCosts[ri];
+
+      // deque
+      while (!dq.empty() &&
+             chargeTimes[dq.front()] + (ri - le + 1) * sum > budget) {
+        if (dq.front() == le) {
+          dq.pop_front();
+        }
+        sum -= runningCosts[le++];
+      }
+
+      ans = max(ans, ri - le + 1);
+    }
+    return ans;
+  }
+};
diff --git a/daily/Sep14.cc b/daily/Sep14.cc
new file mode 100644
index 0000000..8ae4ae3
--- /dev/null
+++ b/daily/Sep14.cc
@@ -0,0 +1,63 @@
+#include <iostream>
+using namespace std;
+
+class Solution {
+ public:
+  string removeStars1(string s) {
+    string ans;
+    stack<char> stk;
+    for (char c : s) {
+      if (c == '*') {
+        stk.pop();
+      } else {
+        stk.push(c);
+      }
+    }
+    while (!stk.empty()) {
+      char c = stk.top();
+      ans.push_back(c);
+      stk.pop();
+    }
+    std::reverse(ans.begin(), ans.end());
+    return ans;
+  }
+
+  string removeStars2(string s) {
+    string ans;
+    deque<char> dq;
+    for (char c : s) {
+      if (c == '*') {
+        dq.pop_back();
+      } else {
+        dq.push_back(c);
+      }
+    }
+
+    while (!dq.empty()) {
+      ans.push_back(dq.front());
+      dq.pop_front();
+    }
+    return ans;
+  }
+
+  /**
+   * @brief remove stars in a string
+   * Use the stack to solve this problem, however, use stack or deque
+   * is a little bit complex
+   * Remember that `string` also has the `pop_back()` api, just use string.
+   *
+   * @param s
+   * @return string
+   */
+  string removeStars3(string s) {
+    string ans;
+    for (char c : s) {
+      if (c == '*') {
+        ans.pop_back();
+      } else {
+        ans += c;
+      }
+    }
+    return ans;
+  }
+};
diff --git a/daily/Sep8.cc b/daily/Sep8.cc
new file mode 100644
index 0000000..2f5b9df
--- /dev/null
+++ b/daily/Sep8.cc
@@ -0,0 +1,26 @@
+#include <vector>
+
+class Solution {
+public:
+  vector<int> sortedSquares(vector<int> nums) {
+    int len = nums.size();
+    for (int i = 0; i < len ; i++) {
+      nums[i] = nums[i] * nums[i];
+    }
+
+    vector<int> ans(len, 0);
+    int le = 0, ri = len - 1;
+    int pivot = len - 1;
+    while (le <= ri) {
+      if (nums[le] > nums[ri]) {
+        ans[pivot] = nums[le]; // get larger
+        le++;
+      } else {
+        ans[pivot] = nums[ri];
+        ri--;
+      }
+      pivot--;
+    }
+    return ans;
+  }
+}