Submission #981586

#	Time	Username	Problem	Language	Result	Execution time	Memory
981586		kh0i	Count Squares (CEOI19_countsquares)	C++17	100 / 100	1904 ms	141204 KiB

countsquares

#include "bits/stdc++.h"
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif

using ll = long long;
using pii = pair<int, int>;

#define F first
#define S second
#define sz(x) (int)((x).size())
#define all(x) (x).begin(), (x).end()

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll get_rand(ll l, ll r) {
    assert(l <= r);
    return uniform_int_distribution<ll> (l, r)(rng);
}

void solve(){
    int n, m;
    cin >> n >> m;
    vector<int> a(n), b(m);
    for(int i = 0; i < n; ++i) cin >> a[i];
    for(int i = 0; i < m; ++i) cin >> b[i];
    map<int, ll> mp;
    ll res = 0;
    for(int i = 0; i < n; ++i)
        for(int j = 0; j < i; ++j)
            ++mp[a[i] - a[j]];
    for(int i = 0; i < m; ++i)
        for(int j = 0; j < i; ++j)
            res += mp[b[i] - b[j]];
    cout << res;
}

int32_t main() {
    cin.tie(nullptr)->sync_with_stdio(0);
    #define task "troll"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int test = 1;
//    cin >> test;
    for(int i = 1; i <= test; ++i){
//        cout << "Case #" << i << ": ";
        solve();
    }
    #ifdef LOCAL
        cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    #endif
    return 0;
}

Compilation message (stderr)

countsquares.cpp: In function 'int32_t main()':
countsquares.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
countsquares.cpp:46:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 40 / 40
• Subtask 3: 53 / 53