A very easy triangle counting game

N points on the circle, and the two adjacent points are connected (Note: N and 1 are adjacent). Then all the points (I, I + 2) are connected, how many triangles can be formed?

Train of Thought: Find the rule

N = 3, CNT = 1;

N = 4, CNT = 8;

N = 5 CNT = 35 (5*2 + 5*2 + 5 + 5 + 5 );

N = 6 CNT = 32 (6*2 + 6*2 + 6 + 2 );

N = 7, CNT = 35 (7*2 + 7*2 + 7 );

N = 8, CNT = 40 (8*2 + 8*2 + 8)

N> 6; CNT = 5 * N;

AC code:

 1 #include<stdlib.h> 2 #include<stdio.h> 3 #include<string.h> 4 #define m 20121111 5 int main() 6 { 7     int t,n; 8     scanf("%d",&t); 9     int cas=1;10     while(t--)11     {12         int ans;13         scanf("%d",&n);14         if(n<3)15             ans = 0;16         else if(n == 3)17             ans = 1;18         else if(n == 4)19             ans = 8;20         else if(n == 5)21             ans = 35;22         else if(n == 6)23             ans = 32;24         else25             ans = 5*n;26         printf("Case #%d: %d\n",cas++,ans%m);27     }28     return 0;29 }

 

A very easy triangle counting game