Submission #733998

#	Time	Username	Problem	Language	Result	Execution time	Memory
733998		lorenzoferrari	Fish (IOI08_fish)	C++17	0 / 100	532 ms	58860 KiB

fish

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

static constexpr int N = 5e5+5;

struct fish {
    int l;
    int g;
    bool operator<(const fish& oth) {
        return l < oth.l;
    }
};

static int f[N];    // frq of each colour
static int ff[N];   // frq of each frq
set<int> s;         // {j | ff[j] != 0}
vector<int> pw[N];

static void inc(int c, int m) {
    if (ff[f[c]] == 1) {
        s.erase(f[c]);
    }
    --ff[f[c]];
    ++f[c];
    ++ff[f[c]];
    if (ff[f[c]] == 1) {
        s.insert(f[c]);
    }
    pw[f[c]+1].push_back(pw[f[c]+1].back() * ((f[c]+1) % m) % m);
}

static void dec(int c, int m) {
    assert(f[c]);
    if (ff[f[c]] == 1) {
        s.erase(f[c]);
    }
    --ff[f[c]];
    --f[c];
    ++ff[f[c]];
    if (ff[f[c]] == 1) {
        s.insert(f[c]);
    }
    pw[f[c]+1].push_back(pw[f[c]+1].back() * ((f[c]+1) % m) % m);
}

static int calc(int c, int m) {
    int ans = 1;
    for (int j : s) {
        ans = ans * pw[j+1][ff[j]] % m;
    }
    return ans;
}

int main() {
    for (int i = 0; i < N; ++i) {
        pw[i].emplace_back(1);
    }

    int n; cin >> n;
    int k; cin >> k;
    int m; cin >> m;
    vector<fish> a(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i].l >> a[i].g; --a[i].g;
    }
    sort(begin(a), end(a));
    vector<int> last(k);
    for (int i = 0; i < n; ++i) {
        last[a[i].g] = i;
    }

    int ans = 0;
    vector<vector<int>> fut(n);
    for (int r = 0, l = 0; r < n; ++r) {
        if (last[a[r].g] != r) continue;
        while (2*a[l].l <= a[r].l) {
            if (last[a[l].g] <= r) {
                inc(a[l].g, m);
            } else {
                fut[last[a[l].g]].push_back(l);
            }
            ++l;
        }
        for (int i : fut[r]) {
            inc(a[i].g, m);
        }
        ans += calc(a[r].g, m);
        if (ans >= m) ans -= m;
    }
    
    cout << ans << "\n";
}

Compilation message (stderr)

fish.cpp:32:13: warning: 'void dec(int, int)' defined but not used [-Wunused-function]
   32 | static void dec(int c, int m) {
      |             ^~~

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