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-rw-r--r--I_anno/Programmazione_2/algorithms/mergesort.cc52
-rw-r--r--I_anno/Programmazione_2/algorithms/quicksort.cc38
2 files changed, 90 insertions, 0 deletions
diff --git a/I_anno/Programmazione_2/algorithms/mergesort.cc b/I_anno/Programmazione_2/algorithms/mergesort.cc
new file mode 100644
index 0000000..68d28cb
--- /dev/null
+++ b/I_anno/Programmazione_2/algorithms/mergesort.cc
@@ -0,0 +1,52 @@
+#include<iostream>
+
+using namespace std;
+
+void merge(int A[], int l, int q, int r) {
+ int i = l;
+ int j = q+1;
+ int k = l;
+ int B[r];
+
+ while((i <= q) && (j <= r)) {
+ if(A[i] <= A[j])
+ B[k] = A[i++];
+ else
+ B[k] = A[j++];
+
+ k++;
+ }
+
+ while(i <= q)
+ B[k++] = A[i++];
+
+ while(j <= r)
+ B[k++] = A[j++];
+
+ for(k = l; k <= r; ++k)
+ A[k] = B[k];
+}
+
+void mergesort(int A[], int l, int r) {
+ if(l < r) {
+ int q = (l+r)/2;
+ mergesort(A, l, q);
+ mergesort(A, q+1, r);
+ merge(A, l, q, r);
+ }
+}
+
+
+int main() {
+ int a[] = {7,1,22,3,2,12,27,31,6};
+ for(int i = 0; i < 9; ++i) {
+ cout << a[i] << ' ';
+ }
+ cout << endl;
+ mergesort(a, 0, 8);
+ for(int i = 0; i < 9; ++i) {
+ cout << a[i] << ' ';
+ }
+
+ return 0;
+}
diff --git a/I_anno/Programmazione_2/algorithms/quicksort.cc b/I_anno/Programmazione_2/algorithms/quicksort.cc
new file mode 100644
index 0000000..a646840
--- /dev/null
+++ b/I_anno/Programmazione_2/algorithms/quicksort.cc
@@ -0,0 +1,38 @@
+#include<iostream>
+
+using namespace std;
+
+int partition(int A[], int l, int r) {
+ int x = A[r];
+ int i = l-1;
+
+ for(int j = l; j < r; ++j) {
+ if(A[j] <= x) {
+ swap(A[++i], A[j]);
+ }
+ }
+ swap(A[++i], A[r]);
+ return i;
+}
+
+void quicksort(int A[], int l, int r) {
+ if(l < r) {
+ int q = partition(A, l, r);
+ quicksort(A, l, q-1);
+ quicksort(A, q+1, r);
+ }
+}
+
+int main() {
+ int a[] = {7,1,22,3,2,12,27,31,6};
+ for(int i = 0; i < 9; ++i) {
+ cout << a[i] << ' ';
+ }
+ cout << endl;
+ quicksort(a, 0, 9);
+ for(int i = 0; i < 9; ++i) {
+ cout << a[i] << ' ';
+ }
+
+ return 0;
+}