delete pics to save space

2.1428.cpp

@@ -0,0 +1,65 @@
+#include<cstdio>
+#include<cstring>
+const int maxn=100005;
+int T,n,r;
+int a[maxn],b[maxn];
+int lowbit(int x) { return x&-x; }
+inline int sum(int x)
+{
+	int res=0;
+	while(x>0)
+	{
+		res=res+b[x];
+		x-=lowbit(x);
+	}
+	return res;
+}
+inline void add(int x,int d)
+{
+	a[x]=a[x]+d;
+	while(x<=r)
+	{
+		b[x]=b[x]+d;
+		x+=lowbit(x);
+	}
+}
+inline void set(int x,int d) { add(x,d-a[x]); }
+int v[maxn],x[maxn],y[maxn];
+long long res;
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&T);
+	while(T-->0)
+	{
+		scanf("%d",&n);
+		r=0;
+		for(int i=1;i<=n;i++)
+		{
+			scanf("%d",&v[i]);
+			if(v[i]>r) r=v[i];
+		}
+		memset(a,0,sizeof(a));
+		memset(b,0,sizeof(b));
+		for(int i=1;i<=n;i++)
+		{
+			set(v[i],1);
+			x[i]=sum(v[i]-1);
+		}
+		memset(a,0,sizeof(a));
+		memset(b,0,sizeof(b));
+		for(int i=n;i>=1;i--)
+		{
+			set(v[i],1);
+			y[i]=sum(v[i]-1);
+		}
+		res=0;
+		for(int i=2;i<=n-1;i++) res=res
+									+(long long)x[i]*(n-i-y[i])
+									+(long long)(i-x[i]-1)*y[i];
+		printf("%lld\n",res);
+	}
+	return 0;
+}