INSERTION-SORT(A) 1 for j ← 2 to length[A] 2 do key ← A[j] 3 ▹ Insert A[j] into the sorted sequence A[1 ‥ j - 1]. 4 i ← j - 1 5 while i > 0 and A[i] > key 6 do A[i + 1] ← A[i] 7 i ← i - 1 8 A[i + 1] ← key 时间复杂度:O(n^2) (我们通常考虑最坏情况下的复杂度)