#20453: 沒那麼暴力的暴力解


jack621224 (YJLegend)


把每一項都加起來之後從第一項開始遍歷

eg:

1 2 3

sum = 6

開始遍歷

arr[0] = 1 * (6-1) = 5

arr[1] = 2 * (5-2) = 6

arr[2] = 3 * (3-3) = 0

ans = 5 + 6 + 0

#20768: Re:沒那麼暴力的暴力解


IanWang20061204 (詭譎)


把每一項都加起來之後從第一項開始遍歷

eg:

1 2 3

sum = 6

開始遍歷

arr[0] = 1 * (6-1) = 5

arr[1] = 2 * (5-2) = 6

arr[2] = 3 * (3-3) = 0

ans = 5 + 6 + 0

幫忙補充一下,sum也要用unsighned long long喔