Create nCr-main

Author: manitajay

Templates/nCr-main

@@ -0,0 +1,76 @@
+
+
+ll power(ll a,ll b){
+ ll val=a;
+
+
+ ll ans=1;
+
+ ll temp=b;
+ while(temp!=0){
+ if(temp%2){
+ ans*=(val);
+ ans%=mod;
+ }
+ val*=val;
+ val%=mod;
+ temp/=2;
+ }
+
+ return ans;
+
+
+
+
+}
+
+ll sum(ll x,ll y){
+
+ return (x%mod + y%mod)%mod;
+
+}
+
+
+ll mul(ll x,ll y){
+
+ return ((x%mod)*(y%mod))%mod;
+
+}
+
+
+ll subs(ll x,ll y){
+ return (x%mod - y%mod + mod)%mod;
+}
+
+
+
+ll fact[3000005];
+ll inver[3000005];
+
+void calculate(){
+ // cout<<"YES"<<endl;
+
+ fact[0]=1;
+ fact[0]%=mod;
+
+
+ for(ll i=1;i<=3000004;i++){
+ fact[i]=(fact[i-1]*i)%mod;
+ }
+
+ inver[3000004]=power(fact[3000004],mod-2);
+
+ for(ll i=3000004;i>0;i--){
+ inver[i-1]=inver[i]*i;
+ inver[i-1]%=mod;
+ }
+
+
+
+}
+
+
+ll nCr(ll n,ll r){
+ return (((fact[n]*inver[r])%mod)*inver[n-r])%mod;
+}
+