World is exploding tree-like array + discretization

Given a sequence A with length n,count how many quadruple (a,b,c,d) satisfies:A≠B≠C≠D,1≤A<B≤N,1≤C<D≤N,Aa <ab,A c >ad A≠b≠c≠d,1≤a<b≤n,1≤c<d≤n,aa<ab,ac>ad.

Inputthe input consists of multiple test cases.
Each test case is begin with a integer n

The next line contains n integersa1,a2? An A1,a2?an.
1≤n≤50000 1≤n≤50000
0 & #x2264; A i & #x2264; 1 e 9 " > 0≤ ai≤1e9 0≤ai≤1e9 Outputfor each test case,output a line contains an integer. Sample Input

42 4 1 341 2 3 4

Sample Output

10

Because the relative size relationship is considered, the data is discretized first, then the elements that are larger than I or smaller than I are recorded in a tree-like array, all the numbers are calculated, the overlapping is discussed, and the coincident elements are subtracted.

#include <iostream>#include<cstdio>#include<cmath>#include<cstring>#include<sstream>#include<algorithm>#include<queue>#include<vector>#include<cmath>#include<map>#include<stack>#include<fstream>#include<Set>#include<memory>#include<bitset>#include<string>#include<functional>using namespaceStd;typedefLong LongLL;#defineMAXN 500009LL PRE_MAX[MAXN], PRE_MIN[MAXN], POST_MAX[MAXN], POST_MIN[MAXN]; LL A[MAXN], TMP[MAXN]; LL T[MAXN], N; ll Lowbit (ll x) {returnx& (-x);}voidUpdate (LL x) { while(x <=MAXN) {T[x]+=1; X+=lowbit (x); }}ll Getsum (ll x) {ll sum=0;  while(X >0) {sum+=T[x]; X-=lowbit (x); }    returnsum;}intMain () { while(SCANF ("%lld", &n)! =EOF) {memset (T,0,sizeof(T));  for(LL i =1; I <= N; i++) scanf ("%lld", &A[i]); memcpy (TMP, A,sizeof(a)); Sort (tmp+1, TMP + n +1); LL Len= Unique (tmp +1, TMP + n +1) -tmp;  for(LL i =1; I <= N; i++) A[i]= Lower_bound (tmp +1, TMP + len +1, A[i])-tmp;  for(LL i =1; I <= N; i++) {update (a[i]); Pre_min[i]= Getsum (A[i]-1); Pre_max[i]= i-getsum (A[i]);        } LL sum1, sum2; Sum1= Sum2 =0;  for(inti =1; I <= N; i++) {Post_min[i]= Getsum (A[i]-1) -Pre_min[i]; Post_max[i]= N-getsum (A[i])-Pre_max[i]; Sum1+=Post_min[i]; Sum2+=Post_max[i]; } LL ans= sum1*sum2;  for(inti =1; I <= N; i++) {ans-= pre_min[i] *Pre_max[i]; Ans-= pre_min[i] *Post_min[i]; Ans-= post_max[i] *Pre_max[i]; Ans-= post_max[i] *Post_min[i]; } printf ("%lld\n", ans); }}

World is exploding tree-like array + discretization