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