hdu 2042 - 不容易系列之二

题意：（略）太长了

解法：找规律，发现A[i]=A[i-1]*2-2;

#include<stdlib.h>

#include<string.h>

#include<stdio.h>

#include<math.h>

#define N 31

int a
={3};

void init(){

int i;

for(i=1;i<N;i++){

a[i]=a[i-1]*2-2;//这个就是递推式

}

}

int main(){

int n,i;

init();

while(scanf("%d",&n)!=EOF){

while(n--){

int tmp;

scanf("%d",&tmp);

printf("%d\n",a[tmp]);

}

}

}

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