Create MergeSort.cpp

MergeSort.cpp

@@ -0,0 +1,65 @@
+class Solution {
+public:
+    void merge(vector<int>&arr,int l,int mid,int r){
+        if(l>=r)    return;
+        vector<int>a(mid-l+1);
+        vector<int>b(r-mid);
+        for(int i=l;i<=mid;i++)     a[i-l] = arr[i];
+        for(int i=mid+1;i<=r;i++)     b[i-mid-1] = arr[i];
+        int x=0;
+        int y=0;
+        int i = l;
+        while(x<a.size() && y<b.size()){
+            if(a[x]<=b[y]){
+                arr[i]=a[x];
+                x++;
+            }
+            else{
+                arr[i]=b[y];
+                y++;
+            }
+            i++;
+        }
+        while(x<a.size()){
+            arr[i]=a[x];
+            x++;
+            i++;
+        }
+        while(y<b.size()){
+            arr[i]=b[y];
+            y++;
+            i++;
+        }
+    }
+    void mergeSort(vector<int>&arr,int l, int r){
+        if(l<r){
+            int mid = (l+r)/2;
+            mergeSort(arr,l,mid);
+            mergeSort(arr,mid+1,r);
+            merge(arr,l,mid,r);
+        }
+    }
+    vector<int> sortArray1(vector<int>& nums) {
+        mergeSort(nums,0,nums.size()-1);
+        return nums;
+    }
+
+    void countSort(vector<int> &arr, int n){
+		int mx = INT_MIN;
+		for(int i=0;i<n;i++)	mx = max(mx,arr[i]);
+		vector<int> count(mx+1);
+		for(int i=0;i<n;i++)	count[arr[i]]++;
+		for(int i=1;i<=mx;i++)	count[i]+=count[i-1];
+
+		int output[n];
+		for(int i=n-1;i>=0;i--){
+			output[--count[arr[i]]] = arr[i];
+		}
+		for(int i=0;i<n;i++)	arr[i] = output[i];
+	}
+
+    vector<int> sortArray(vector<int>& nums) {
+        countSort(nums, nums.size());
+        return nums;
+    }
+};