#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define FOR(i,l,r) for(int i=(l);i<=(r);i++)
#define ROF(i,r,l) for(int i=(r);i>=(l);i--)
using namespace std;
ll infl=1000000000000000007;
int inf=1000000007;
ll mod;
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
const int N=1000007;
ll pot(ll x,ll p) {ll res=1;for(;p;p>>=1) {if(p&1) res=res*x%mod; x=x*x%mod;} return res;}
ll fac[N];
ll inv[N];
int n;
ll calc(vector<int>t)
{
debug(t);
int a=sz(t),S=0;
FOR(i,0,a-1) S+=t[i];
ll res=fac[S];
FOR(i,0,a-1)
{
int it=a-1;
FOR(j,1,t[i])
{
while(t[it]<j) it--;
res=res*inv[t[i]-j+it-i+1]%mod;
}
}
return res;
}
map<vector<int>,ll>mem;
int cnt;
ll get(vector<int>t)
{
ll X=mem[t];
if(X) return X;
cnt++;
ll res=0;
int a=sz(t);
bool nie=0;
FOR(i,1,a-1) if(t[i]<t[i-1]) nie=1;
if(nie)
{
bool is=0;
FOR(i,0,a-1)
{
if(t[i]>0&&(i==0||t[i-1]<t[i]))
{
t[i]--;
res+=get(t);
t[i]++;
is=1;
}
}
if(!is) res=1;
res%=mod;
}
else
{
vector<int>w=t;
reverse(all(w));
res=calc(w);
}
return mem[t]=res;
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int a,b,c;
cin>>a>>b>>c>>mod;
int t=a+b-1-c;
n=a*b-t*(t+1)/2;
fac[0]=1;
for(ll i=1;i<=n;i++) fac[i]=fac[i-1]*i%mod;
FOR(i,1,n) inv[i]=pot(i,mod-2);
vector<int>r(a);
FOR(i,0,a-1) r[i]=b;
FOR(i,1,t) r[a-1-(t-i)]-=i;
debug(r);
ll ans=calc(r);
if(t==0) ans=ans*ans%mod;
else ans=ans*get(r)%mod;
cout<<n<<" "<<ans<<endl;
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 | #include <bits/stdc++.h> #define ll long long #define ld long double #define endl '\n' #define st first #define nd second #define pb push_back #define sz(x) (int)(x).size() #define all(x) (x).begin(), (x).end() #define FOR(i,l,r) for(int i=(l);i<=(r);i++) #define ROF(i,r,l) for(int i=(r);i>=(l);i--) using namespace std; ll infl=1000000000000000007; int inf=1000000007; ll mod; #ifdef DEBUG auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";} auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";} #define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X) #else #define debug(...){} #endif const int N=1000007; ll pot(ll x,ll p) {ll res=1;for(;p;p>>=1) {if(p&1) res=res*x%mod; x=x*x%mod;} return res;} ll fac[N]; ll inv[N]; int n; ll calc(vector<int>t) { debug(t); int a=sz(t),S=0; FOR(i,0,a-1) S+=t[i]; ll res=fac[S]; FOR(i,0,a-1) { int it=a-1; FOR(j,1,t[i]) { while(t[it]<j) it--; res=res*inv[t[i]-j+it-i+1]%mod; } } return res; } map<vector<int>,ll>mem; int cnt; ll get(vector<int>t) { ll X=mem[t]; if(X) return X; cnt++; ll res=0; int a=sz(t); bool nie=0; FOR(i,1,a-1) if(t[i]<t[i-1]) nie=1; if(nie) { bool is=0; FOR(i,0,a-1) { if(t[i]>0&&(i==0||t[i-1]<t[i])) { t[i]--; res+=get(t); t[i]++; is=1; } } if(!is) res=1; res%=mod; } else { vector<int>w=t; reverse(all(w)); res=calc(w); } return mem[t]=res; } signed main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int a,b,c; cin>>a>>b>>c>>mod; int t=a+b-1-c; n=a*b-t*(t+1)/2; fac[0]=1; for(ll i=1;i<=n;i++) fac[i]=fac[i-1]*i%mod; FOR(i,1,n) inv[i]=pot(i,mod-2); vector<int>r(a); FOR(i,0,a-1) r[i]=b; FOR(i,1,t) r[a-1-(t-i)]-=i; debug(r); ll ans=calc(r); if(t==0) ans=ans*ans%mod; else ans=ans*get(r)%mod; cout<<n<<" "<<ans<<endl; return 0; } |
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