andere implementierung des heapsort

heapsort2.c

@@ -0,0 +1,49 @@
+#include <stdio.h>
+
+void swap(int* data, unsigned int i, unsigned int j) {
+    int tmp = data[i];
+    data[i] = data[j];
+    data[j] = tmp;
+}
+
+void siftdown(int* data, unsigned int n, unsigned int i) {
+    unsigned int left, right, ip;
+    while( i < n ) {
+        left = 2 * i + 1;
+        right = 2 * i + 2;
+        if( !(left < n) ) break;
+
+        ip = left;
+
+        if( right < n && data[ip] < data[right] ) ip = right;
+        if( data[ip] < data[i] ) break;
+
+        swap(data,i,ip);
+        i = ip;
+    }
+}
+
+void heapcreate(int* data, unsigned int n) {
+    for(unsigned int i = n/2; i > 0; i--) {
+        siftdown(data, n, i);
+    }
+    siftdown(data, n, 0);
+}
+
+void heapsort(int* data, unsigned int n) {
+    heapcreate(data, n);
+    for(unsigned int heapsize = n-1; heapsize > 0; heapsize--) {
+        swap(data,0,heapsize);
+        siftdown(data,heapsize,0);
+    }
+}
+
+int main( int argc, char *argv[] ) {
+    int data[10] = { 3,7,5,1,2,8,9,0,4,6 };
+    heapsort(data, 10);
+
+    for(unsigned int i = 0; i < 10; i++) printf("%d ", data[i]);
+    printf("\n");
+
+	return 0;
+}