摘要：
A * B Problem Plus Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 25361 Accepted Submission(s): 阅读全文
摘要：
考虑差分sum[i] = a[1]+...+a[i] + delta[1]*i + delta[2]*(i-1)+delta[3]*(i-2)+...+delta[i]*1 // a[i]为原始数组 = sigma(a[x])+sigma(delta[x]*(i+1-x)) = sigma(a[x] 阅读全文