diff --git a/Combination Sum II/combination_sum_II.py b/Combination Sum II/combination_sum_II.py
new file mode 100644
index 0000000..e69de29
diff --git a/Next Permutation/new_permutation.java b/Next Permutation/new_permutation.java
new file mode 100644
index 0000000..be92e64
--- /dev/null
+++ b/Next Permutation/new_permutation.java	
@@ -0,0 +1,30 @@
+class Solution {
+    public void nextPermutation(int[] nums) {
+        
+        int infPoint=-1;
+        for(int i=nums.length-1;i>0;i--){
+            if (nums[i]>nums[i-1]){
+                infPoint=i-1;
+                break;
+            } 
+        }        
+        
+        if (infPoint != -1){
+            for(int j=nums.length-1;j>0;j--){
+                if (nums[infPoint]<nums[j]){
+                    nums[j]+=nums[infPoint];
+                    nums[infPoint]=nums[j]-nums[infPoint];
+                    nums[j]-=nums[infPoint];
+                    break;
+                }
+            }
+        }
+        
+        for (int i=infPoint+1; i<=infPoint+(nums.length-1-infPoint)/2;i++){
+            nums[i]+=nums[nums.length+infPoint-i];
+            nums[nums.length+infPoint-i]=nums[i]-nums[nums.length+infPoint-i];
+            nums[i]-=nums[nums.length+infPoint-i];
+        }
+        
+    }
+}
\ No newline at end of file
diff --git a/Next Permutation/nextPermutation.cpp b/Next Permutation/nextPermutation.cpp
new file mode 100644
index 0000000..49e85a7
--- /dev/null
+++ b/Next Permutation/nextPermutation.cpp	
@@ -0,0 +1,19 @@
+class Solution {
+public:
+    void nextPermutation(vector<int>& nums) {
+        int n=nums.size();
+        int i,j;
+        for(i=n-2;i>=0;i--){
+            if(nums[i]<nums[i+1]) break;
+        }
+        if(i<0){
+            reverse(nums.begin(),nums.end());
+            return;
+        }
+        for(j=n-1;j>i;j--){
+            if(nums[j]>nums[i]) break;
+        }
+        swap(nums[j],nums[i]);
+        reverse(nums.begin()+i+1,nums.end());
+    }
+};
diff --git a/trappingRainWater.cpp b/trappingRainWater.cpp
new file mode 100644
index 0000000..aaa370b
--- /dev/null
+++ b/trappingRainWater.cpp
@@ -0,0 +1,18 @@
+class Solution {
+public:
+    int trap(vector<int>& height) {
+        int n=height.size();
+        int left=0,right=n-1,sum=0,mleft=0,mright=0;
+        for(int i=0;i<n;i++){
+            if(height[left]<height[right]){
+                height[left]>=mleft?mleft=height[left]:sum+=(mleft-height[left]);
+                left++;
+            }
+            else{
+                height[right]>=mright?mright=height[right]:sum+=(mright-height[right]);
+                right--;
+            }
+        }
+        return sum;
+    }
+};