题解 | #[NOIP2015]金币#

#include <stdio.h>

int main() {

    int num = 0;
    int day = 0;
    int count = 1;
    int sum = 0;
    scanf("%d", &day);
    for (int i = 0; i < day; i++, num++) {
        if (num == count) {
            num = 0;
            count++;
        }
        sum += count;
    }
    printf("%d", sum);
    return 0;
}