delete pics to save space

1.1908.cpp

@@ -0,0 +1,30 @@
+#include<cstdio>
+#include<cstring>
+const int maxn=5e5+5;
+int n; long long res;
+int a[maxn],b[maxn];
+void GB(int *a,int *b,int len)
+{
+	if(len<=1) return;
+	int M=len/2,p1=0,p2=M,p=0;
+	GB(a,b,M); GB(a+M,b+M,len-M);
+	while(p1<M&&p2<len)
+	{
+		if(a[p1]<=a[p2]) b[p++]=a[p1++];
+		else res+=M-p1,b[p++]=a[p2++];
+	}
+	while(p1<M) b[p++]=a[p1++];
+	while(p2<len) b[p++]=a[p2++];
+	memcpy(a,b,len<<2);
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&n);
+	for(int i=0;i<n;i++) scanf("%d",&a[i]);
+	GB(a,b,n);
+	printf("%lld\n",res);
+	return 0;
+}