#include <stdio.h>
const int u[3] = {1, -3, 2};
const int v[2] = {-2, 3};
int g(int n){
int i, sum = 0;
for (i = 1; i <= n; i++) sum += u[i % 3] * i;
return sum;
}
int main(){
int n, i, sum = 0;
scanf("%d", &n);
for (i = 1; i <= n; i++) {sum += v[i % 2] * g(i);printf(" sum=%d\n",sum);}
printf("%d\n", sum);
getch();
return 0;
}
哪位高手讲下问思路是什么？感激不尽
