feat: add algorithms

1 files changed, 46 insertions, 0 deletions

diff --git a/I_anno/Programmazione_2/algorithms/selectionsort.cc b/I_anno/Programmazione_2/algorithms/selectionsort.cc
new file mode 100644
index 0000000..57dcc17
--- /dev/null
+++ b/I_anno/Programmazione_2/algorithms/selectionsort.cc
@@ -0,0 +1,46 @@
+#include<iostream>
+#include<algorithm>
+
+using namespace std;
+
+void selectionsort(int a[], int n) {
+    for(int i = 0; i < n-1; ++i) {
+        int min = i;
+        for(int j = i+1; j < n; ++j) {
+            if(a[j] < a[min])
+                min = j;
+        }
+
+        swap(a[min], a[i]);
+    }
+}
+
+int min_i(int a[], int i, int j) {
+    if(i == j) return i;
+
+    int k = min_i(a, i+1, j);
+    return (a[i] < a[k]) ? i : k;
+}
+
+void selectionsort_rec(int* a, int b, int e=0) {
+    if(b == e) return;
+
+    int key = min_i(a, e, b-1);
+    if(key != e)
+        swap(a[key], a[e]);
+
+    selectionsort_rec(a, b, e+1);
+}
+
+int main() {
+    int arr[] = {3,450,12,4,-1,0,24,95,123,0};
+    for(int i = 0; i < 10; ++i) {
+        cout << *(arr+i) << ' ';
+    }
+    cout << endl;
+    selectionsort_rec(arr, 10);
+    for(int i = 0; i < 10; ++i) {
+        cout << *(arr+i) << ' ';
+    }
+    return 0;
+}