63 lines
995 B
Plaintext
63 lines
995 B
Plaintext
# Implementation of a stack using a linked list.
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fun Stack_New(T)
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return { count: 0, head: none, type: T };
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fun Stack_Push(stack: Map, value) {
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if type(value) != stack.type:
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error("Invalid type");
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node = {prev: none, item: value};
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node.prev = stack.head;
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stack.head = node;
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stack.count = stack.count + 1;
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}
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fun Stack_Pop(stack: Map) {
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if stack.head == none:
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return none;
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value = stack.head.item;
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stack.head = stack.head.prev;
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stack.count = stack.count - 1;
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return value;
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}
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fun Stack_Print(stack: Map) {
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print("[");
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curr = stack.head;
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while curr != none: {
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print(curr.item);
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curr = curr.prev;
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if curr != none:
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print(", ");
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}
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print("]");
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}
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stack = Stack_New(int);
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Stack_Push(stack, 1);
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Stack_Push(stack, 2);
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Stack_Push(stack, 3);
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Stack_Print(stack);
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print("\n");
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x = Stack_Pop(stack);
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y = Stack_Pop(stack);
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z = Stack_Pop(stack);
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w = Stack_Pop(stack);
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assert(x == 3);
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assert(y == 2);
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assert(z == 1);
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assert(w == none);
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Stack_Print(stack);
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print("\n");
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