35 lines
527 B
C
35 lines
527 B
C
#include <stdio.h>
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int stack[256], top = 0;
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void push(int node);
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void pop(void);
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int main(void){
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int N[1000], train = 0;
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int number, i;
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scanf("%d",&number);
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for(i = 0; i < number; i++) scanf("%d",&N[i]);
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i = 0;
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int if_ok = 1;
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while(i < number){
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if(train > number){
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if_ok = 0;
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break;
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}
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if(stack[top-1] != N[i]){
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push(++train);
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}
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else pop(),i++;
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}
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if(!if_ok) printf("No\n");
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else printf("Yes\n");
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return 0;
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}
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void push(int node){
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stack[top++] = node;
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}
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void pop(void){
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stack[top] = 0;
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top--;
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}
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