delete pics to save space

8.2457.cpp

@@ -0,0 +1,53 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+#include<vector>
+using namespace std;
+const int maxn=200005;
+int n;
+pair<int,int> a[maxn];
+inline bool cmp(int x,int y) { return a[x]<a[y]||(a[x]==a[y]&&x<y); }
+vector<int> b[maxn]; int cnt;
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&n);
+	for(int i=1;i<=n;i++)
+	{
+		scanf("%d",&a[i].first);
+		a[i].second=i;
+	}
+	sort(a+1,a+1+n);
+	for(int i=1;i<=n;i++)
+	{
+		b[++cnt].push_back(a[i].second);
+		while(i+1<=n&&a[i].first==a[i+1].first) b[cnt].push_back(a[++i].second);
+	}
+	int flg=0,res=1,now=0x3f3f3f3f;
+	for(int i=1;i<=cnt;i++)
+	{
+		int s=b[i].size();
+		if(flg)
+		{
+			if(now<b[i][0]) now=b[i][s-1];
+			else
+			{
+				now=b[i][0];
+				res++; flg=0;
+			}
+		}
+		else
+		{
+			if(now>b[i][s-1]) now=b[i][0];
+			else
+			{
+				now=b[i][s-1];
+				flg=1;
+			}
+		}
+	}
+	printf("%d\n",res);
+	return 0;
+}