题解 | 金币

//  1 2 2 3  3 3 4 4 4 5 5 5 5 6 6 6 6 6 7 7 7 7 7 8 8 8 8 8 9 9 9 9 9 10 10 10 10 10 11 11 11 11 11 12 12 12 12 12 13 13 13 13 13

#include <stdio.h>

int main() {
    int N;
    int k = 1; //数值及 持续天数
    int sum_k = 0, sum_k_1 = 0;
    int sum = 0;
    scanf("%d", &N);
    while (1) {
        /* code */
        sum_k += k;
        if (sum_k >= N) {
            break;
        }
        k++;

    }


    for (int i = 1; i <= k - 1; i++) {
        for (int j = 1; j <= i; j++) {
            sum += i;
        }
    }
    for (int i = 1; i <= k - 1; i++) {
        /* code */
        sum_k_1 += i;
    }

    for (int i = 1; i <= N - sum_k_1; i++) {
        /* code */
        sum += k;
    }

    printf("%d", sum);

    return 0;
}