27 lines
406 B
C
27 lines
406 B
C
#include<stdio.h>
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int fact[]={1,1,2,6,24,120,720,5040,40320};
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int factorial(int n) {
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return fact[n];
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}
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int cnk4(int n, int k) {
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int res = factorial(n);
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res /= factorial(n-k);
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res /= factorial(k);
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return res;
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}
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int main(void)
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{
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int n, k;
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scanf("%d%d", &n,&k);
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//Input: 3 2 output: 3
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//~ Input: 8 3
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//~ output: 56
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printf("%d",cnk4(n,k));
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return 0;
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}
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