diff --git a/.zed/debug.json b/.zed/debug.json
index cff2839..48a4749 100644
--- a/.zed/debug.json
+++ b/.zed/debug.json
@@ -1,9 +1,9 @@
 [
   {
-    "label": "Debug td6 exo1",
+    "label": "Debug td6",
     "build": {
       "command": "gcc",
-      "args": ["-o", "./exe", "-lm", "-g", "td6/exo1.c"],
+      "args": ["-o", "./exe", "-lm", "-g", "td6/td6.c"],
       "cwd": "$ZED_WORKTREE_ROOT",
     },
     "program": "$ZED_WORKTREE_ROOT/exe",
diff --git a/td5/td5.c b/td5/td5.c
index 24dff6e..eab21ae 100644
--- a/td5/td5.c
+++ b/td5/td5.c
@@ -82,7 +82,7 @@ const int sorted[] = {0, 0, 3, 5, 5, 9};
 const int n = 6;
 
 int main() {
-    int t1[6];
+    int t1[n];
     memcpy(t1, t, n * sizeof(int));
     insertion_sort(t1, n);
     assert(memcmp(t1, sorted, n * sizeof(int)) == 0);
diff --git a/td6/exo1.c b/td6/exo1.c
deleted file mode 100644
index c3704e0..0000000
--- a/td6/exo1.c
+++ /dev/null
@@ -1,57 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-
-void print_t(int t[], int len) {
-    printf("[");
-    for (int i = 0; i < len; i++) {
-        printf("%d,", t[i]);
-    }
-    printf("]\n");
-}
-
-void quicksort(int t[], int len) {
-    if (len < 2) {
-        return;
-    }
-    int ip = len / 2;
-    int p = t[ip];
-    int a = 0;
-    int b = len - 1;
-
-    while (a < b) {
-        while (t[a] < p && a < b) {
-            a++;
-            if (a >= ip) {
-                int tmp = t[a];
-                t[a] = t[ip];
-                t[ip] = tmp;
-                ip++;
-                a--;
-            }
-        }
-        while (t[b] > p && a < b) {
-            b--;
-            if (b <= ip) {
-                int tmp = t[b];
-                t[b] = t[ip];
-                t[ip] = tmp;
-                ip--;
-                b++;
-            }
-        }
-        int tmp = t[a];
-        t[a] = t[b];
-        t[b] = tmp;
-        a++;
-        b--;
-    }
-    quicksort(t, ip);
-    quicksort(t + ip + 1, len - ip - 1);
-}
-
-int main() {
-    int t[] = {0, -7, 4, -2, 2, -3};
-    quicksort(t, 6);
-    print_t(t, 6);
-    return 0;
-}
diff --git a/td6/td6.c b/td6/td6.c
new file mode 100644
index 0000000..6471868
--- /dev/null
+++ b/td6/td6.c
@@ -0,0 +1,49 @@
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+void printt(int t[], int n) {
+    printf("[");
+    for (int i = 0; i < n; i++) {
+        printf("%d,", t[i]);
+    }
+    printf("]\n");
+}
+
+void swap(int t[], int i, int j) {
+    int tmp = t[i];
+    t[i] = t[j];
+    t[j] = tmp;
+}
+
+void quicksort(int t[], int n) {
+    if (n <= 1) {
+        return;
+    }
+    int a = 0;
+    int b = n - 1;
+    int p = t[n - 1];
+    while (a < b) {
+        if (t[a] <= p)
+            a++;
+        else if (t[b] >= p)
+            b--;
+        else {
+            swap(t, a, b);
+        }
+    }
+    swap(t, b, n - 1);
+    quicksort(t, b);
+    quicksort(t + b + 1, n - b - 1);
+}
+
+const int t[] = {5, 3, 9, 0, 5, 0};
+const int sorted[] = {0, 0, 3, 5, 5, 9};
+const int n = 6;
+
+int main() {
+    int t1[n];
+    memcpy(t1, t, n * sizeof(int));
+    quicksort(t1, n);
+    assert(memcmp(t1, sorted, n * sizeof(int)) == 0);
+}