diff --git a/DS/C/Lab/Shortcodes/BST.c b/DS/C/Lab/Shortcodes/BST.c
new file mode 100644
index 0000000..e6b7afe
--- /dev/null
+++ b/DS/C/Lab/Shortcodes/BST.c
@@ -0,0 +1,92 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+typedef struct TreeNode {
+    int d;
+    struct TreeNode *l, *r;
+} T;
+
+T *c(int d) {
+    T *n = malloc(sizeof(T));
+    n->d = d;
+    n->l = n->r = NULL;
+    return n;
+}
+
+T *i(T *r, int d) {
+    if (!r) return c(d);
+    if (d < r->d) r->l = i(r->l, d);
+    else if (d > r->d) r->r = i(r->r, d);
+    return r;
+}
+
+T *f(T *r) {
+    while (r->l) r = r->l;
+    return r;
+}
+
+T *d(T *r, int k) {
+    if (!r) return NULL;
+    if (k < r->d) r->l = d(r->l, k);
+    else if (k > r->d) r->r = d(r->r, k);
+    else {
+        if (!r->l) {
+            T *t = r->r;
+            free(r);
+            return t;
+        } else if (!r->r) {
+            T *t = r->l;
+            free(r);
+            return t;
+        }
+        T *t = f(r->r);
+        r->d = t->d;
+        r->r = d(r->r, t->d);
+    }
+    return r;
+}
+
+void t(T *r) {
+    if (r) {
+        t(r->l);
+        printf("%d ", r->d);
+        t(r->r);
+    }
+}
+
+int s(T *r, int k, int *p) {
+    if (!r) return 0;
+    int l = s(r->l, k, p);
+    if (l) return l;
+    if (++*p == k) return *p;
+    return s(r->r, k, p);
+}
+
+int main() {
+    T *r = NULL;
+    int c, v;
+    while (1) {
+        printf("\n1. Insert\n2. Delete\n3. Search\n4. Display\n5. Exit\n");
+        scanf("%d", &c);
+        if (c == 1) {
+            scanf("%d", &v);
+            r = i(r, v);
+        } else if (c == 2) {
+            scanf("%d", &v);
+            r = d(r, v);
+        } else if (c == 3) {
+            scanf("%d", &v);
+            int p = 0, f = s(r, v, &p);
+            printf(f ? "Found at %d\n" : "Not found\n", f);
+        } else if (c == 4) {
+            t(r);
+            printf("\n");
+        } else if (c == 5) {
+            break;
+        } else {
+            printf("Invalid\n");
+        }
+    }
+    free(r);
+    return 0;
+}
diff --git a/DS/C/Lab/Shortcodes/DoublyLLShort.c b/DS/C/Lab/Shortcodes/DoublyLLShort.c
new file mode 100644
index 0000000..9dbfa6c
--- /dev/null
+++ b/DS/C/Lab/Shortcodes/DoublyLLShort.c
@@ -0,0 +1,195 @@
+#include<stdio.h>
+#include<stdlib.h>
+typedef struct N {
+    int d;
+    struct N *p, *n;
+} N;
+
+N *h;
+
+void i(int d) {
+    N *n = malloc(sizeof(N));
+    n->d = d;
+    n->n = 0;
+    if (!h) {
+        n->p = 0;
+        h = n;
+        return;
+    }
+    N *t = h;
+    while (t->n) t = t->n;
+    t->n = n;
+    n->p = t;
+}
+
+void delete_rear() {
+    if (!h) {
+        puts("Empty");
+        return;
+    }
+    if (!h->n) {
+        free(h);
+        h = 0;
+        return;
+    }
+    N *t = h;
+    while (t->n) t = t->n;
+    t->p->n = 0;
+    free(t);
+}
+
+void ip(int d, int p) {
+    N *n = malloc(sizeof(N));
+    n->d = d;
+    if (p == 1) {
+        n->p = 0;
+        n->n = h;
+        if (h) h->p = n;
+        h = n;
+        return;
+    }
+    N *t = h;
+    for (int i = 1; i < p - 1 && t; i++) t = t->n;
+    if (!t) {
+        puts("Out of range");
+        return;
+    }
+    n->n = t->n;
+    n->p = t;
+    if (t->n) t->n->p = n;
+    t->n = n;
+}
+
+void dp(int p) {
+    if (!h) {
+        puts("Empty");
+        return;
+    }
+    N *t = h;
+    if (p == 1) {
+        h = h->n;
+        if (h) h->p = 0;
+        free(t);
+        return;
+    }
+    for (int i = 1; i < p && t; i++) t = t->n;
+    if (!t) {
+        puts("Out of range");
+        return;
+    }
+    t->p->n = t->n;
+    if (t->n) t->n->p = t->p;
+    free(t);
+}
+
+void ia(int d, int k) {
+    N *n = malloc(sizeof(N));
+    n->d = d;
+    N *t = h;
+    while (t && t->d != k) t = t->n;
+    if (!t) {
+        puts("Not found");
+        return;
+    }
+    n->n = t->n;
+    n->p = t;
+    if (t->n) t->n->p = n;
+    t->n = n;
+}
+
+void ib(int d, int k) {
+    N *n = malloc(sizeof(N));
+    n->d = d;
+    if (!h) {
+        puts("Empty");
+        return;
+    }
+    if (h->d == k) {
+        n->n = h;
+        n->p = 0;
+        h->p = n;
+        h = n;
+        return;
+    }
+    N *t = h;
+    while (t->n && t->n->d != k) t = t->n;
+    if (!t->n) {
+        puts("Not found");
+        return;
+    }
+    n->n = t->n;
+    n->p = t;
+    t->n->p = n;
+    t->n = n;
+}
+
+void t() {
+    for (N *t = h; t; t = t->n) printf("%d ", t->d);
+    puts("");
+}
+
+void r() {
+    N *t = 0, *c = h;
+    while (c) {
+        t = c->p;
+        c->p = c->n;
+        c->n = t;
+        c = c->p;
+    }
+    if (t) h = t->p;
+}
+
+int main() {
+    int c, d, p, k;
+    while (1) {
+        puts("\n1.Insert rear\n2.Delete rear\n3.Insert position\n4.Delete position\n5.Insert after\n6.Insert before\n7.Traverse\n8.Reverse\n9.Exit");
+        printf("Choice: ");
+        scanf("%d", &c);
+        switch (c) {
+            case 1:
+                printf("Data: ");
+                scanf("%d", &d);
+                i(d);
+                break;
+            case 2:
+                delete_rear();
+                break;
+            case 3:
+                printf("Data: ");
+                scanf("%d", &d);
+                printf("Position: ");
+                scanf("%d", &p);
+                ip(d, p);
+                break;
+            case 4:
+                printf("Position: ");
+                scanf("%d", &p);
+                dp(p);
+                break;
+            case 5:
+                printf("Data: ");
+                scanf("%d", &d);
+                printf("After: ");
+                scanf("%d", &k);
+                ia(d, k);
+                break;
+            case 6:
+                printf("Data: ");
+                scanf("%d", &d);
+                printf("Before: ");
+                scanf("%d", &k);
+                ib(d, k);
+                break;
+            case 7:
+                t();
+                break;
+            case 8:
+                r();
+                break;
+            case 9:
+                exit(0);
+            default:
+                puts("Invalid");
+        }
+    }
+}
diff --git a/DS/C/Lab/Shortcodes/dcll.c b/DS/C/Lab/Shortcodes/dcll.c
new file mode 100644
index 0000000..7333e22
--- /dev/null
+++ b/DS/C/Lab/Shortcodes/dcll.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct c { int d; struct c *n, *p; } *C;
+C l = NULL;
+
+C new_c(int v) {
+    C t = (C)malloc(sizeof(struct c));
+    t->d = v; t->n = t->p = NULL; return t;
+}
+
+void insert_beg(int v) {
+    C t = new_c(v);
+    if (!l) { l = t; l->n = l->p = l; }
+    else {
+        t->n = l->n;
+        l->n->p = t;
+        t->p = l;
+        l->n = t;
+    }
+}
+
+void del_end() {
+    if (!l) printf("List is empty");
+    else {
+        C p = l->p;
+        p->n = l->n;
+        l->n->p = p;
+        free(l);
+        l = p;
+    }
+}
+
+void traverse() {
+    if (!l) return;
+    C c = l->n;
+    do { printf("%d ", c->d); c = c->n; } while (c != l->n);
+    printf("\n");
+}
+
+int main() {
+    char cont = 'y'; int ch;
+    while (cont == 'y') {
+        printf("1. Insert at beginning\n2. Delete at end\n3. Traverse\n");
+        scanf("%d", &ch);
+        if (ch == 1) { int v; scanf("%d", &v); insert_beg(v); }
+        else if (ch == 2) { del_end(); printf("Element deleted\n"); }
+        else if (ch == 3) { traverse(); }
+        printf("Continue? (y/n)\n");
+        fflush(stdin);
+        scanf(" %c", &cont);
+    }
+    return 0;
+}
diff --git a/DS/C/Lab/Shortcodes/dllconcs.c b/DS/C/Lab/Shortcodes/dllconcs.c
new file mode 100644
index 0000000..d282df5
--- /dev/null
+++ b/DS/C/Lab/Shortcodes/dllconcs.c
@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node {
+    int d;
+    struct node *l, *r;
+} *N;
+
+void concat(N *X1, N *X2) {
+    if (*X1 == NULL) *X1 = *X2;
+    else if (*X2) {
+        N t = *X1;
+        while (t->r) t = t->r;
+        t->r = *X2;
+        (*X2)->l = t;
+    }
+}
+
+N new_node(int d) {
+    N n = (N)malloc(sizeof(struct node));
+    n->d = d;
+    n->l = n->r = NULL;
+    return n;
+}
+
+void insert(N *h, int d) {
+    N n = new_node(d);
+    if (!*h) *h = n;
+    else {
+        N t = *h;
+        while (t->r) t = t->r;
+        t->r = n;
+        n->l = t;
+    }
+}
+
+void print(N h) {
+    while (h) {
+        printf("%d ", h->d);
+        h = h->r;
+    }
+    printf("\n");
+}
+
+int main() {
+    N X1 = NULL, X2 = NULL;
+    insert(&X1, 1);
+    insert(&X1, 2);
+    insert(&X1, 3);
+    insert(&X2, 4);
+    insert(&X2, 5);
+    concat(&X1, &X2);
+    print(X1);
+    return 0;
+}
diff --git a/DS/C/Lab/Shortcodes/tree.c b/DS/C/Lab/Shortcodes/tree.c
new file mode 100644
index 0000000..0f6cde2
--- /dev/null
+++ b/DS/C/Lab/Shortcodes/tree.c
@@ -0,0 +1,69 @@
+#include<stdio.h>
+#include<stdlib.h>
+#define M 100
+
+typedef struct N *P;
+typedef struct N{int d;P l,r;}N;P root;
+
+int t=-1;P stk[M];
+P cn(int v){P n=malloc(sizeof(N));n->d=v;n->l=n->r=NULL;return n;}
+
+void ct(int n){
+    int v,i;char dir[50];P p=NULL,c;
+    for(int k=0;k<n;k++){
+        scanf("%d",&v);P tmp=cn(v);
+        if(!root)root=tmp;
+        else{
+            scanf("%s",dir);c=root;
+            for(i=0;dir[i]&&c;i++){
+                p=c;c=(dir[i]=='L'||dir[i]=='l')?c->l:c->r;
+            }
+            if(c||dir[i]){free(tmp);continue;}
+            (dir[i-1]=='L'||dir[i-1]=='l')?(p->l=tmp):(p->r=tmp);
+        }
+    }
+}
+
+int e(){return t==-1;}void p(P n){if(t<M-1)stk[++t]=n;}
+P o(){return e()?NULL:stk[t--];}
+
+void io(P n){while(1){while(n){p(n);n=n->l;}if(!(n=o()))break;printf("%d ",n->d);n=n->r;}}
+void po(P n){while(1){while(n){p(n);printf("%d ",n->d);n=n->l;}if(!(n=o()))break;n=n->r;}}
+void pso(P n){while(1){if(n){p(n);n=n->l;}else{if(e())break;P tmp=stk[t]->r;if(!tmp){tmp=o();printf("%d ",tmp->d);while(!e()&&tmp==stk[t]->r){tmp=o();printf("%d ",tmp->d);}}else n=tmp;}}}
+
+P pn(P n,int v){if(!n)return NULL;if((n->l&&n->l->d==v)||(n->r&&n->r->d==v))return n;P l=pn(n->l,v);return l?l:pn(n->r,v);}
+
+int md(P n){if(!n)return 0;int l=md(n->l),r=md(n->r);return(l>r?l:r)+1;}
+int pa(P n,int v){if(!n)return 0;if(n->d==v)return 1;if(pa(n->l,v)||pa(n->r,v)){printf("%d ",n->d);return 1;}return 0;}
+void cl(P n,int *c){if(n&&!n->l&&!n->r)(*c)++;if(n){cl(n->l,c);cl(n->r,c);}}
+
+int main(){
+    int n,ch,v,lc;
+    printf("\nBinary Tree Menu:\n");
+    printf("1. Create Tree\n");
+    printf("2. Inorder Traversal\n");
+    printf("3. Preorder Traversal\n");
+    printf("4. Postorder Traversal\n");
+    printf("5. Find Parent of Node\n");
+    printf("6. Find Max Depth\n");
+    printf("7. Print Ancestors of Node\n");
+    printf("8. Count Leaf Nodes\n");
+    printf("9. Exit\n");
+    do{
+        printf("Enter choice: ");
+        scanf("%d",&ch);
+        switch(ch){
+            case 1:printf("Enter number of nodes: ");scanf("%d",&n);ct(n);break;
+            case 2:printf("Inorder: ");io(root);puts("");break;
+            case 3:printf("Preorder: ");po(root);puts("");break;
+            case 4:printf("Postorder: ");pso(root);puts("");break;
+            case 5:printf("Enter value to find parent: ");scanf("%d",&v);P p=pn(root,v);p?printf("Parent: %d\n",p->d):puts("Node not found");break;
+            case 6:printf("Max Depth: %d\n",md(root));break;
+            case 7:printf("Enter value to find ancestors: ");scanf("%d",&v);pa(root,v)?puts(""):puts("No ancestors found");break;
+            case 8:lc=0;cl(root,&lc);printf("Leaf count: %d\n",lc);break;
+            case 9:break;
+            default:puts("Invalid choice");
+        }
+    }while(ch!=9);
+    return 0;
+}