21 lines
290 B
C
21 lines
290 B
C
#include <stdio.h>
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unsigned long long C(int m,int n);
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int main(void){
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int m,n;
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scanf("%d %d",&m,&n);
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printf("%llu\n",C(m,n));
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return 0;
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}
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unsigned long long C(int m,int n){
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int i,c = 1,tmp;
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for(i = 0; i < n; i++){
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c *= m-i;
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}
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for(i = 0; i < n; i++){
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c /= n-i;
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}
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return c;
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}
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