#include<bits/stdc++.h> using namespace std; long long n,a[300005],kk=0,node,fen[300005],cnt,mount=0; unordered_map<long long,long long> mp; set<long long> s; vector<long long> v[300005]; void up(long long u,long long val) { while(u<=n) { fen[u]+=val; u+=(u&(-u)); } } long long qq(long long u) { cnt=0; while(u>0) { cnt+=fen[u]; u-=(u&(-u)); } return cnt; } long long query(long long l,long long r) { return qq(r)-qq(l-1); } int main() { scanf("%lld",&n); for(int i=1;i<=n;i++) { scanf("%lld",&a[i]); s.insert(a[i]); } for(auto it=s.begin();it!=s.end();it++) { if(mp[*it]==0) { ++kk; mp[*it]=kk; } } for(int i=1;i<=n;i++) { v[mp[a[i]]].push_back(i); } for(int i=1;i<=n;i++) { //printf("%d\n",i); for(int j=0;j<v[i].size();j++) { node=v[i][j]; //printf("%lld ",node); mount+=query(1,node-1)*query(node+1,n); } //printf("\n"); for(int j=0;j<v[i].size();j++) { node=v[i][j]; up(node,1); } } printf("%lld\n",mount); }

Mountains.cpp: In function 'int main()':
Mountains.cpp:52:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |         for(int j=0;j<v[i].size();j++)
      |                     ~^~~~~~~~~~~~
Mountains.cpp:59:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |         for(int j=0;j<v[i].size();j++)
      |                     ~^~~~~~~~~~~~
Mountains.cpp:31:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |     scanf("%lld",&n);
      |     ~~~~~^~~~~~~~~~~
Mountains.cpp:34:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |         scanf("%lld",&a[i]);
      |         ~~~~~^~~~~~~~~~~~~~