题解 | #[NOIP2015]金币#

#include <stdio.h>

int main() {
    int k=0,sum=0,count =0,l =1;
    scanf("%d",&k);
    for(int i =1;i<=k;i++)
    {
        if(count<l)
        {
            sum += l;
            count++;
        }
        if(count==l)
        {
            l++;
            count=0;  
        }
    }
    printf("%d\n",sum);
    return 0;
}