trouble with efficiency

Author: mantertius

sum.c

@@ -0,0 +1,90 @@
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+#include <stdlib.h>
+#define MAX 100001
+typedef struct node
+{
+    int data;
+    struct node* previous;
+}NODE;
+
+typedef struct head
+{
+    int size;
+    NODE* top;
+}STACK;
+
+STACK* init_list()
+{   
+    STACK* new_head = (STACK*) malloc(sizeof(STACK));
+    new_head->top = NULL;
+    new_head->size = 0;
+    return new_head;
+}
+int isEmpty(STACK* top)
+{
+    return(top->size == 0);
+}
+void push(STACK* stack, int item)
+{
+    NODE* new_top = (NODE*) malloc(sizeof(NODE*));
+    new_top->data = item;
+    if(isEmpty(stack))
+    {
+        new_top->previous = NULL;
+    }
+    else
+    {
+        new_top->previous = stack->top;
+    }
+    stack->size++;
+    stack->top = new_top;
+}
+STACK* pop(STACK* stack)
+{
+    NODE* popped = stack->top;
+    if(isEmpty(stack))
+    {
+        return NULL;
+    }
+    popped->previous == NULL;
+    stack->top = stack->top->previous;
+    stack->size--;
+
+    return popped;
+}
+
+int main() {
+    STACK* x = init_list();
+    STACK* y = init_list();
+    STACK* z = init_list();
+    int eof_seeker;
+    int len1= 0;
+    int len2 = 0;
+    int X[MAX];
+    int Y[MAX];
+    do //gets the first number
+    {
+        eof_seeker = scanf("%d", &X[len1]);
+        if (eof_seeker != EOF)
+        {
+            push(x,X[len1]);
+            len1++;
+        }
+         
+    } while (eof_seeker != EOF);
+    do //gets the second number
+    {
+        eof_seeker = scanf("%d", &Y[len2]);
+        if (eof_seeker != EOF)
+        {
+            push(y,Y[len2]);
+            len2++;
+        }
+         
+    } while (eof_seeker != EOF);
+    
+    
+	return 0;
+}