제출 #1281985

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1281985		cheska	Mountains (NOI20_mountains)	C++20	0 / 100	2104 ms	268264 KiB

Mountains

#include <bits/stdc++.h>
using namespace std;
#define pii pair<long long, long long>
#define ppii pair<pii, pii> 
#define tiii tuple<long long, long long, long long>
#define g0 get<0>
#define g1 get<1>
#define g2 get<2>
#define f first
#define s second
#define pb push_back
const long long N = 5005;
const long long MOD = 1e9+7;
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace __gnu_pbds;

#define ordered_set tree<long long, null_type,less<long long>, rb_tree_tag,tree_order_statistics_node_update> 
vector<long long> compress(vector<long long> b, long long n) {
    map<long long, long long> m;
    vector<pii> c(n);
    for (long long i = 0; i < n; i++) {
        c[i] = {b[i], i};
    }
    sort(c.begin(), c.end());
    long long cr = 0;
    for (long long i = 0; i < n; i++) {
        if (m.count(c[i].f)) b[c[i].s] = m[c[i].f];
        else {
            b[c[i].s] = cr;
            m[c[i].f] = cr;
            cr++;
        }
    }
    return b;
}
signed main() {
    freopen("in.in", "r", stdin);
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    long long n; cin >> n;
    vector<long long> b(n);
    map<long long, vector<long long>> a;
    for (long long i = 0; i < n; i++) {
        cin >> b[i];
    }
    b = compress(b, n);
    for (long long i = 0; i < n; i++) {
        a[b[i]].pb(i);
    }
    ordered_set ss;
    long long ans = 0;
    for (auto i : a) {
        for (long long j : i.s) {
            long long k = ss.order_of_key(j);
            ans += k*(ss.size()-k);
        }
        for (long long j : i.s) {
            ss.insert(j);
        }
    }
    cout << ans;
}

컴파일 시 표준 에러 (stderr) 메시지

Mountains.cpp: In function 'int main()':
Mountains.cpp:38:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |     freopen("in.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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