归并排序的迭代表示/自底向上归并

#include <iostream>
#include <stdlib.h>

using namespace std;
#define N 100

//合并序列中的s:m-1和m:e两个子序列
void merge(int array[], int s, int m, int e) {
    int ta[N], i, j, k = 0;    
    i = s;
    j = m;
    while (i < m && j <= e) {
        if (array[i] < array[j]) {
            ta[k++] = array[i++];
        } else {
            ta[k++] = array[j++];
        }
    }
    while (i < m) {
        ta[k++] = array[i++];
    } 
    while (j <= e) {
        ta[k++] = array[j++];
    }
    i = s;
    k = 0;
    while (i <= e) {
        array[i++] = ta[k++];
    }
}

//自底向上归并
void buttomUpSort(int array[], int length) {
    int i = 1, s, m, e, t;
    while ((length / i) >= 1) {    //依次从2, 4, 8......至序列被分成两部分向上归并
        s = 0;
        while (1) {
            m = s + i;
            if (m >= length)//若此段序列孤立（及原序列被划分成奇数个部分，最后一部分不做合并，进入到下一次合并）
                break;
            else {
                e = ((t = m + i - 1) < length)?t:length - 1;//最后一段序列的截止位为length-1
                merge(array, s, m, e);
            }
            s += i*2;
        }
        i *= 2;
    }
}

int main(int args, char **argv) {
    int array[N];
    for (int i = 0; i < N; ++i) {
        array[i] = rand() % 100;
    }
    for (int i = 0; i < N; i++) {
        cout << '\t' << array[i];
    }
    cout << endl;
    buttomUpSort(array, N);
    for (int i = 0; i < N; i++) {
        cout << '\t' << array[i];
    }
    return 0;
}