"Data structure Seventh Week" sort (top)

1. Simple sorting

void Bubble_sort (Elementype a[], int N) {for (P = N-1; P >= 0; p--) {flag = 0;for (i = 0; i < P; ++i) {if (A[i] > A[i+1]) {Swap (a[i],a[i+1]); flag = 1;}} if (flag = = 0) {break;}}}

Best case: Order t = O (N)

Worst case: Reverse T = O (n^2)

2. Insert Sort

void Insertion_sort (ElementType a[], int N) {for (P = 1; P < N; ++P) {tmp = a[p];for (i = P; i > 0 && a[i-1] > Tmp;-I.) {A[I] = a[i-1];} A[i] = Tmp;}}

Best case: Order t = O (N)

Worst case: Reverse T = O (n^2)

Theorem: A sequence consisting of any n different elements has an average of n (N-1)/4 reverse pairs.

Theorem: The average time complexity of any algorithm that is ordered only by exchanging adjacent two elements is Ω (n^2).

To improve the efficiency of the algorithm, we must eliminate more than 1 reverse order every time! 2 elements at a distance from each exchange!

　　

"Data structure Seventh Week" sort (top)