19 lines
434 B
C
19 lines
434 B
C
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#include <stdio.h>
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int main(void){
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int count,i;
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unsigned long long n[3][40]={0};
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n[0][0] = 1, n[1][0] = 1, n[2][0] = 1;
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n[0][1] = 3, n[1][1] = 2, n[2][1] = 3;
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for(i = 2; i < 40; i++){
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n[0][i] = n[0][i-1] + n[1][i-1] + n[2][i-1];
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n[1][i] = n[0][i-1] + n[2][i-1];
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n[2][i] = n[0][i-1] + n[1][i-1] + n[2][i-1];
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}
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while(scanf("%d",&count) == 1){
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printf("%llu\n",n[0][count-1]+n[1][count-1]+n[2][count-1]);
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}
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return 0;
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}
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