Ncr Or
(lib/util/ncr-or.hpp)

• View this file on GitHub
• Last update: 2020-06-22 16:37:39+09:00
• Include: #include "lib/util/ncr-or.hpp"

Code

#pragma once
template<class Int,uint_fast64_t md=mod>
Int ncr(lint n,lint r){
	if(n<r||n<0||r<0)return Int(0);
	Int ncr_res=1,ncr_div=1;
	for(int i=0; i<r; ++i)ncr_res*=(n-i),ncr_div*=(r-i);
	return ncr_res/ncr_div;
}

/*
* @title Ncr O(r)
*/

#line 2 "lib/util/ncr-or.hpp"
template<class Int,uint_fast64_t md=mod>
Int ncr(lint n,lint r){
	if(n<r||n<0||r<0)return Int(0);
	Int ncr_res=1,ncr_div=1;
	for(int i=0; i<r; ++i)ncr_res*=(n-i),ncr_div*=(r-i);
	return ncr_res/ncr_div;
}

/*
* @title Ncr O(r)
*/

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