delete pics to save space

history_source/信息学奥赛一本通/3.1.5.cpp

@@ -0,0 +1,28 @@
+#include<cstdio>
+int top=0,n,*sr,*stack;
+void check()
+{
+	int *p=sr;
+	for(int i=1;i<=n;i++)
+	{
+		if(*p==i)
+		{
+			p++;
+			while(top>0&&stack[top-1]==*p) p++,top--;
+			continue;
+		}
+		else stack[top++]=i;
+	}
+	while(top>0&&stack[top-1]==*p) p++,top--;
+	if(top==0) printf("YES\n");
+	else printf("NO\n");
+}
+int main()
+{
+	scanf("%d",&n);
+	sr=new int[n];
+	stack=new int[n+5];
+	for(int i=0;i<n;i++) scanf("%d",sr+i);
+	check();
+	return 0;
+}