2024-10-14 15:03:17
2024-10-14 16:56:01
1. n 不能太大,会溢出的
#include <stdio.h>
int foo(int n)
{
int i, sum = 0;
for (i = 1; i <= n; i++)
sum += i * (n + 1 - i);
return sum;
}
int main(void)
{
int n;
scanf("%d", &n);
printf("%d\n", foo(n));
return 0;
}
2024-10-14 12:21:13
2024-10-14 14:10:42
#include<stdio.h>
#include<stdlib.h>
#define N 100
int an(int n)
{
return n*(n+1)/2;
}
int bn(n){
if(n%2==0)
return -n*(n+1);
else
return n*(n+1);
}
int main(){
int i,sa=0,sb=0;
for(i=0;i<N;i++)
{
sa += an(i);
sb += bn(i);
}
printf("S1=%d\nS2=%d\n",sa,sb);
return 0;
}
2024-10-14 17:39:33
long f1(int n){
int i,j;
long m,s;
for(i=1;i<=n;i++){
for(j=1,j<=i;j++)
m+=j;
s+=m;
}
return s;
}
long f2(int n){
int i,j,k;
long m;
k = 1;
for(i = 1;i<=n;i++){
j = i+1;
m += k*i*j;
k = -k;
}
return m;
}