Merge pull request #225 from danghai/master

Add partition sort algorithm

sorting/partitionSort.c

@@ -0,0 +1,62 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+void swap(int *a, int *b) {
+  int tmp = *a;
+  *a = *b;
+  *b = tmp;
+}
+
+int partition(int arr[], int low, int high) {
+  int pivot = arr[low];
+  int i = low - 1, j = high + 1;
+
+	while(1) {
+    /* Find leftmost element >= pivot */
+    do {
+        i++;
+    } while(arr[i] < pivot);
+
+        /* Find rightmost element <= pivot */
+    do {
+        j--;
+    } while(arr[j] > pivot);
+
+    /* if two pointers met */
+    if (i >= j)
+        return j;
+
+    swap(&arr[i], &arr[j]);
+  }
+}
+
+void partitionSort(int arr[], int low, int high) {
+    if(low < high) {
+        int value = partition(arr, low, high);
+        partitionSort(arr, low, value);
+        partitionSort(arr, value + 1, high);
+	}
+}
+
+void printArray(int arr[], int n) {
+  int i;
+  for(i = 0; i < n; i++)
+      printf("%d ", arr[i]);
+  printf("\n");
+}
+
+int main() {
+  int arr[20];
+  int i, range = 100;
+  for(i = 0; i < 20; i++) {
+      arr[i] = rand() % range + 1;
+  }
+  int size = sizeof arr / sizeof arr[0];
+  printf("Array: \n");
+  printArray(arr, size);
+  partitionSort(arr, 0, size - 1);
+  printf("Sorted Array: \n");
+  printArray(arr, size);
+
+  return 0;
+}