64 lines
1.1 KiB
C
64 lines
1.1 KiB
C
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#include <ctype.h>
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#include <stdio.h>
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#include <stdlib.h>
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typedef struct stack {
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int val;
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struct stack *next;
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} stack;
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stack *push(stack *st, int val) {
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stack *new = malloc(sizeof(stack));
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new->next = st;
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new->val = val;
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return new;
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}
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int isEmpty(stack *st) { return st == NULL; }
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int peek(stack *st) { return st->val; }
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stack *pop(stack *st) {
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stack *tmp = st->next;
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free(st);
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return tmp;
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}
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int main(void) {
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stack *st = NULL;
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int size = 0;
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int in;
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int last;
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int lastUsed = 0;
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int centFound = 0;
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while (scanf("%d,", &in) != EOF) {
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size++;
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if (!isEmpty(st) && peek(st) == in) {
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st = pop(st);
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} else if (lastUsed == 1 && last == in) {
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st = pop(st);
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st = pop(st);
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centFound = 1;
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} else {
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if (!isEmpty(st)) {
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last = peek(st);
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lastUsed = 1;
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}
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// printf("PUSHING: %d\n", in);
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st = push(st, in);
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}
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}
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if (size > 0 && isEmpty(st) && centFound == 1) {
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printf("Yes");
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} else if (size == 1) {
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printf("Yes");
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} else {
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printf("No");
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}
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return 0;
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}
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