#include <bits/stdc++.h>
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
*/
using namespace std;
// using namespace __gnu_pbds;
using namespace chrono;
// mt19937 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
/*
template <class T> using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;
*/
//***************** CONSTANTS *****************
//***************** GLOBAL VARIABLES *****************
//***************** AUXILIARY STRUCTS *****************
template <typename T>
struct BIT{
int n;
vector<T> tree;
BIT(int _n){
this->n = _n + 1;
tree.resize(n, 0);
}
void increment(int idx, T val){
for(int i = idx + 1; i < n; i += (i & (-i)))
tree[i] += val;
}
T query(int idx){
T sum = 0;
for(int i = idx + 1; i > 0; i -= (i & (-i)))
sum += tree[i];
return sum;
}
};
//***************** MAIN BODY *****************
void solve(){
int N;
cin >> N;
pair<int64_t, int> pre[N + 1];
pre[0] = {0, 0};
for(int i = 1; i <= N; i++){
cin >> pre[i].first;
pre[i].second = i;
pre[i].first += pre[i-1].first;
}
int64_t P;
cin >> P;
for(int i = 1; i <= N; i++) pre[i].first -= P*1LL*i;
sort(pre, pre + N + 1);
int compress[N + 1], idx = 0;
compress[pre[0].second] = idx;
for(int i = 1; i <= N; i++){
idx += (pre[i].first != pre[i-1].first);
compress[pre[i].second] = idx;
}
BIT<int> s(idx + 1);
int64_t ans = 0;
for(int i = 0; i <= N; i++){
ans += s.query(compress[i]);
s.increment(compress[i], 1);
}
cout << ans << '\n';
}
//***************** *****************
int32_t main(){
ios_base::sync_with_stdio(NULL);
cin.tie(NULL);
#ifdef LOCAL
auto begin = high_resolution_clock::now();
#endif
int tc = 1;
// cin >> tc;
for (int t = 0; t < tc; t++)
solve();
#ifdef LOCAL
auto end = high_resolution_clock::now();
cout << fixed << setprecision(4);
cout << "Execution Time: " << duration_cast<duration<double>>(end - begin).count() << "seconds" << endl;
#endif
return 0;
}
/*
If code gives a WA, check for the following :
1. I/O format
2. Are you clearing all global variables in between tests if multitests are a thing
3. Can you definitively prove the logic
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
460 KB |
Output is correct |
2 |
Correct |
2 ms |
332 KB |
Output is correct |
3 |
Correct |
2 ms |
332 KB |
Output is correct |
4 |
Correct |
255 ms |
32304 KB |
Output is correct |
5 |
Correct |
138 ms |
13072 KB |
Output is correct |
6 |
Correct |
218 ms |
23548 KB |
Output is correct |
7 |
Correct |
225 ms |
27204 KB |
Output is correct |
8 |
Correct |
203 ms |
18380 KB |
Output is correct |
9 |
Correct |
275 ms |
33344 KB |
Output is correct |
10 |
Correct |
220 ms |
24868 KB |
Output is correct |