Submission #173732

#	Time	Username	Problem	Language	Result	Execution time	Memory
173732		stefdasca	Žarulje (COI15_zarulje)	C++14	0 / 100	34 ms	3320 KiB

zarulje

#include<bits/stdc++.h>
#define god dimasi5eks
#pragma GCC optimize("O3")
#define fi first
#define se second
#define pb push_back
#define pf push_front
#define mod 1000000007
#define dancila 3.14159265359
#define eps 1e-9

// #define fisier

using namespace std;

typedef long long ll;


int add(int a, int b)
{
    ll x = a+b;
    if(x >= mod)
        x -= mod;
    if(x < 0)
        x += mod;
    return x;
}
ll mul(ll a, ll b)
{
    return (a*b) % mod;
}

ll pw(ll a, ll b)
{
    ll ans = 1;
    while(b)
    {
        if(b & 1)
            ans = (ans * a) % mod;
        a = (a * a) % mod;
        b >>= 1;
    }
    return ans;
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
long long rand_seed()
{
    long long a = rng();
    return a;
}
int n, k, val, v[200002], vv[200002], ign[200002];
ll fact[200002], inv[200002];
ll C(int n, int k)
{
    return mul(fact[n], mul(inv[k], inv[n-k]));
}
int solve(int val)
{
    for(int i = 1; i <= n; ++i)
        ign[i] = 0;
    for(int i = val; i > 1; --i)
        if(v[i] < v[i-1])
            ign[i-1] = 1;
    for(int i = val; i < n; ++i)
        if(v[i] < v[i+1])
            ign[i+1] = 1;
    int nn = 0;
    int st = 0;
    int dr = 0;
    for(int i = 1; i <= n; ++i)
    {
        if(!ign[i])
            vv[++nn] = v[i];
        if(i == val)
            st = nn-1, dr = nn+1;
    }
    int ans = 1;
    bool prveq = 0;
    int lst = 0;
    while(st >= 1 && dr <= nn)
    {
        if(vv[st] == vv[dr])
        {
            int xx = st;
            while(xx && vv[xx] == vv[st])
                --xx;
            int yy = dr;
            while(yy <= nn && vv[yy] == vv[dr])
                ++yy;
            ans = mul(ans, C(st - xx + yy - dr, st - xx));
            prveq = 1;
            lst = v[st];
            st = xx;
            dr = yy;
        }
        else
            if(vv[st] > vv[dr])
            {
                int xx = st;
                while(xx && vv[xx] == vv[st])
                    --xx;
                st = xx;
            }
            else
            {
                int yy = dr;
                while(yy <= n && vv[yy] == vv[dr])
                    ++yy;
                dr = yy;
            }
    }
    return ans;
}
int main()
{

    #ifdef fisier
        ifstream f("input.in");
        ofstream g("output.out");
    #endif

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> k;
    for(int i = 1; i <= n; ++i)
        cin >> v[i];
    fact[0] = inv[0] = 1;
    for(int i = 1; i <= n; ++i)
    {
        fact[i] = mul(fact[i-1], i);
        inv[i] = pw(fact[i], mod - 2);
    }
    for(; k; --k)
    {
        cin >> val;
        cout << solve(val) << '\n';
    }
    return 0;
}

Compilation message (stderr)

zarulje.cpp: In function 'int solve(int)':
zarulje.cpp:78:10: warning: variable 'prveq' set but not used [-Wunused-but-set-variable]
     bool prveq = 0;
          ^~~~~
zarulje.cpp:79:9: warning: variable 'lst' set but not used [-Wunused-but-set-variable]
     int lst = 0;
         ^~~

• Subtask 1: 0 / 22
• Subtask 2: 0 / 38
• Subtask 3: 0 / 40