d096: 00913 - Joana and the Odd Numbers

https://zerojudge.tw/ShowProblem?problemid=d096

簡單數學題

#include <stdio.h>
int main(){
    long long number ,d ,n , ans , count , total;
    while ( scanf("%lld",&n)!=EOF ){
        d = (1 + n) / 2;
        total = ( 1 + n ) * d /2;
        total = total *2 -1;
        number = total*3 -6;
        printf("%lld\n",number);
    }
    return 0;
}

Allen版解答

#include <iostream>
using namespace std;
int main(){
    int n,ans,row,lineStarter,lastOdd;
    while ( cin>>n ){
        //算出n個奇數該出現在第幾列，也就是row
        row = (1 + n) / 2;
        //算出第row列的開頭數字是多少
        lineStarter = (row-1)*(row-1)*2+1;
        //該列的最後一個奇數的算法
        lastOdd =lineStarter+2*(n-1);
        //lastOdd+(lastOdd-2)+(lastOdd-4) = lastOdd*3 -6
        ans = lastOdd*3 -6;
        cout<<ans<<endl;
    }
    return 0;
}