The Preliminary Contest for ICPC Asia Shanghai 2019

Posted 2022-11-03 inko

D. Counting Sequences I

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

const int MOD = 1000000007;

map<vector<short>, short> m;
vector<short> vec;

void calc(int num1) 
    vector<short> tmp;
    if(num1)
        tmp.push_back(num1);
    int n = vec.size();
    int cur = 1;
    for(int i = 1; i < n; ++i) 
        if(vec[i] != vec[i - 1]) 
            tmp.push_back(cur);
            cur = 1;
         else
            ++cur;
    
    tmp.push_back(cur);
    sort(tmp.begin(), tmp.end());
    m[tmp]++;


void dfs(int last, int cur, ll pro, int sum) 
    for(int i = last; i <= 3000; ++i) 
        int tcur = cur + 1;
        ll tpro = pro * i;
        int tsum = sum + i;
        if(tpro - tsum + tcur > 3000)
            break;

        vec.push_back(i);
        calc(tpro - tsum);
        if(tpro * i - (tsum + i) + (tcur + 1) <= 3000)
            dfs(i, tcur, tpro, tsum);
        vec.pop_back();
    


ll qpow(ll x, int n) 
    ll res = 1;
    while(n) 
        if(n & 1)
            res = res * x % MOD;
        x = x * x % MOD;
        n >>= 1;
    
    return res;


int ans[3005], prod[3005], invprod[3005];

void Init() 
    dfs(2, 0, 1, 0);
    prod[0] = 1;
    for(int i = 1; i <= 3000; ++i) 
        prod[i] = 1ll * prod[i - 1] * i % MOD;
        invprod[i] = qpow(prod[i], MOD - 2);
    
    for(auto mi : m) 
        ll sum = 1;
        int len = 0;
        for(auto vi : mi.first) 
            len += vi;
            sum = (sum * invprod[vi]) % MOD;
        
        sum = (sum * prod[len]) % MOD;
        sum = (sum * mi.second) % MOD;
        ans[len] = (sum + ans[len]) % MOD;
    
    ans[0] = ans[1] = 0;


int main() 
#ifdef Yinku
    freopen("Yinku.in", "r", stdin);
#endif // Yinku
    Init();
    int T;
    scanf("%d", &T);
    while(T--) 
        int n;
        scanf("%d", &n);
        printf("%d\n", ans[n]);
    

H. Luhhy‘s Matrix

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned int uint;

struct Matrix 
    bitset<16> ma[16];
    Matrix() 
    void Clear() 
        for(int i = 0; i < 16; ++i)
            ma[i] = 0;
    
    void one() 
        Clear();
        for(int i = 0; i < 16; ++i)
            ma[i][i] = 1;
    
    Matrix operator*(const Matrix& t)const 
        Matrix res;
        for(int i = 0; i < 16; ++i) 
            for(int k = 0; k < 16; ++k) 
                if(ma[i][k])
                    res.ma[i] ^= t.ma[k];
            
        
        return res;
    
;

stack<Matrix> Stack1, Stack2;
Matrix ProdStack1, tmp;

void Push(uint seed, uint lastans) 
    seed ^= lastans;
    for(int i = 0; i < 16; ++i) 
        seed ^= seed * seed + 15;
        for(int j = 0; j < 16; ++j)
            tmp.ma[i][j] = (seed >> j) & 1;
    
    Stack1.push(tmp);
    ProdStack1 = tmp * ProdStack1;


void Pop() 
    if(Stack2.empty()) 
        tmp.one();
        while(!Stack1.empty()) 
            tmp = tmp * Stack1.top();
            Stack1.pop();
            Stack2.push(tmp);
        
        ProdStack1.one();
    
    Stack2.pop();


uint ans[16][16];

inline void InitAns() 
    uint p17[16], p19[16];
    p17[0] = 1, p19[0] = 1;
    for(int i = 1; i < 16; ++i) 
        p17[i] = p17[i - 1] * 17u;
        p19[i] = p19[i - 1] * 19u;
    
    for(int i = 0; i < 16; ++i) 
        for(int j = 0; j < 16; ++j)
            ans[i][j] = p17[i] * p19[j];
    


uint Calc() 
    if(Stack1.empty() && Stack2.empty())
        return 0;
    tmp = ProdStack1;
    if(!Stack2.empty())
        tmp = tmp * Stack2.top();
    uint res = 0;
    for(int i = 0; i < 16; ++i) 
        for(int j = 0; j < 16; ++j) 
            if(tmp.ma[i][j])
                res += ans[i][j];
        
    
    return res;


inline void Read(uint &x) 
    x = 0;
    char ch = getchar();
    while(ch < '0' || ch > '9')
        ch = getchar();
    while(ch >= '0' && ch <= '9')
        x = (x << 3) + (x << 1) + ch - '0', ch = getchar();


inline void Write(uint x) 
    if(x < 10)
        putchar(x + '0');
    else 
        Write(x / 10);
        putchar(x % 10 + '0');
    


int main() 
#ifdef Yinku
    freopen("Yinku.in", "r", stdin);
#endif // Yinku
    InitAns();
    uint T;
    Read(T);
    while(T--) 
        while(!Stack1.empty())
            Stack1.pop();
        while(!Stack2.empty())
            Stack2.pop();
        ProdStack1.one();
        uint n, t, seed, lastans = 0;
        Read(n);
        for(int i = 1; i <= n; ++i) 
            Read(t), Read(seed);
            if(t == 1)
                Push(seed, lastans);
            else
                Pop();
            lastans = Calc();
            Write(lastans);
            putchar('\n');