Submission #265476

#	Time	Username	Problem	Language	Result	Execution time	Memory
265476		evpipis	Fish (IOI08_fish)	C++11	100 / 100	795 ms	28280 KiB

fish

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

#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef pair<int, int> ii;

const int len = 5e5+5;
int n, k, m;
ii fish[len], big[len];
int fir[len], cnt[len], pos[len], mx[len], tree[4*len];

int add(int a, int b){
    return (a+b)%m;
}

int sub(int a, int b){
    return (m+a-b)%m;
}

int mul(int a, int b){
    return (a*1LL*b)%m;
}

void build(int p, int l, int r){
    if (l == r)
        return void(tree[p] = 1);

    int mid = (l+r)/2;
    build(2*p, l, mid);
    build(2*p+1, mid+1, r);

    tree[p] = mul(tree[2*p], tree[2*p+1]);
}

void update(int p, int l, int r, int i){
    if (l == r)
        return void(tree[p] = add(tree[p], 1));

    int mid = (l+r)/2;
    if (i <= mid)
        update(2*p, l, mid, i);
    else
        update(2*p+1, mid+1, r, i);

    tree[p] = mul(tree[2*p], tree[2*p+1]);
}

int query(int p, int l, int r, int i, int j){
    if (r < i || j < l)
        return 1;
    if (i <= l && r <= j)
        return tree[p];

    int mid = (l+r)/2;
    return mul(query(2*p, l, mid, i, j), query(2*p+1, mid+1, r, i, j));
}

void print(int p = 1, int l = 1, int r = k){
    if (l == r)
        return void(printf("%d ", tree[p]));

    int mid = (l+r)/2;
    print(2*p, l, mid);
    print(2*p+1, mid+1, r);

    if (p == 1)
        printf("\n");
}

namespace brute{
    set<vector<int> > mys;
    vector<int> comb;

    void gen(int i, int spec){
        if (i == 0){
            //printf("now I generated a combination\n");
            //for (int j = 0; j < comb.size(); j++)
              //  printf("%d ", comb[j]);
            //printf("\n");
            return void(mys.insert(comb));}

        int st = 0;
        if (spec == i)
            st = 1;
        for (int j = st; j <= cnt[i]; j++){
            comb.push_back(j);
            gen(i-1, spec);
            comb.pop_back();
        }
    }

    int solve(){
        for (int i = 1; i <= k; i++)
            cnt[i] = 0;
        for (int j = 0; j < n; j++)
            cnt[fish[j].se]++;

        for (int i = k-1, j = n-1; i >= 0; i--){
            while (j >= 0 && big[i].fi < 2*fish[j].fi)
                cnt[fish[j--].se]--;

            int pre = mys.size();

            cnt[big[i].se]++;
            gen(k, big[i].se);
            cnt[big[i].se]--;

            int cur = mys.size();

            printf("brute: i = %d, new_combs = %d\n", i, cur-pre);
        }

        int sz = mys.size();
        //printf("sz = %d\n", sz);
        return sz%m;
    }
};

int solve(){
    /// now fix big[], pos[]
    for (int i = 1; i <= k; i++)
        pos[i] = -1;

    for (int i = n-1, j = 0; i >= 0; i--)
        if (pos[fish[i].se] == -1)
            big[j] = fish[i], pos[fish[i].se] = j++;

    for (int i = 1; i <= k; i++)
        pos[i] = k-pos[i]-1;
    reverse(big, big+k);

    /// fix fir[]
    for (int i = 1; i <= k; i++)
        cnt[i] = 0, mx[i] = -1;
    for (int i = 0; i < k; i++)
        fir[i] = k;

    for (int i = 0, j = 0; i < k; i++){
        while (big[i].fi >= 2*fish[j].fi){
            cnt[fish[j].se]++;
            if (cnt[fish[j].se] == mx[fish[j].se])
                fir[pos[fish[j].se]] = i;
            j++;
        }

        mx[big[i].se] = cnt[big[i].se]+1;
    }

    /// compute the answer
    build(1, 0, k-1);

    int ans = 0;
    for (int i = 0, j = 0; i < k; i++){
        while (big[i].fi >= 2*fish[j].fi)
            update(1, 0, k-1, pos[fish[j++].se]);

        //printf("i = %d, f = (%d, %d), fir = %d\n", i, big[i].fi, big[i].se, fir[i]);

        int full = mul(query(1, 0, k-1, 0, i-1), query(1, 0, k-1, i+1, fir[i]-1));
        int par = mul(query(1, 0, k-1, 0, i-1), sub(query(1, 0, k-1, i, i), 1));


        //printf("ins solve: i = %d, new_combs = %d\n", i, full+par);
        //printf("length = %d, type = %d, par = %d, full = %d\n", big[i].fi, big[i].se, par, full);
        ans = add(ans, add(full, par));
    }

    return ans;
}

int main(){
    //freopen("fish.txt", "r", stdin);

    /// read input and sort fish[]
    scanf("%d %d %d", &n, &k, &m);
    for (int i = 0; i < n; i++)
        scanf("%d %d", &fish[i].fi, &fish[i].se);
    sort(fish, fish+n);

    printf("%d\n", solve());
    //printf("brute: %d\n", brute::solve());
    return 0;
}

Compilation message (stderr)

fish.cpp: In function 'int main()':
fish.cpp:178:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  178 |     scanf("%d %d %d", &n, &k, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
fish.cpp:180:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  180 |         scanf("%d %d", &fish[i].fi, &fish[i].se);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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