Merge pull request #290 from ameybhosle1/master

countingsort

Author: probot-auto-merge[bot]

countingsort.cpp

@@ -0,0 +1,62 @@
+#include<bits/stdc++.h>  
+#include<string.h> 
+using namespace std;  
+#define RANGE 255  
+  
+// The main function that sort  
+// the given string arr[] in  
+// alphabatical order  
+void countSort(char arr[])  
+{  
+    // The output character array  
+    // that will have sorted arr  
+    char output[strlen(arr)];  
+  
+    // Create a count array to store count of inidividul  
+    // characters and initialize count array as 0  
+    int count[RANGE + 1], i;  
+    memset(count, 0, sizeof(count));  
+  
+    // Store count of each character  
+    for(i = 0; arr[i]; ++i)  
+        ++count[arr[i]];  
+  
+    // Change count[i] so that count[i] now contains actual  
+    // position of this character in output array  
+    for (i = 1; i <= RANGE; ++i)  
+        count[i] += count[i-1];  
+  
+    // Build the output character array  
+    for (i = 0; arr[i]; ++i)  
+    {  
+        output[count[arr[i]]-1] = arr[i];  
+        --count[arr[i]];  
+    }  
+  
+    /*  
+    For Stable algorithm  
+    for (i = sizeof(arr)-1; i>=0; --i)  
+    {  
+        output[count[arr[i]]-1] = arr[i];  
+        --count[arr[i]];  
+    }  
+      
+    For Logic : See implementation  
+    */
+  
+    // Copy the output array to arr, so that arr now  
+    // contains sorted characters  
+    for (i = 0; arr[i]; ++i)  
+        arr[i] = output[i];  
+}  
+  
+// Driver  code 
+int main()  
+{  
+    char arr[] = "geeksforgeeks"; 
+  
+    countSort(arr);  
+  
+    cout<< "Sorted character array is " << arr;  
+    return 0;  
+}