归并排序

 1 void merge(int *srcArr, int *tmpArr, int startIdx, int midIdx, int endIdx)
 2 {
 3     int i = startIdx;
 4     int j = midIdx+1;
 5     int k = startIdx;
 6 
 7     while (i<=midIdx && j<=endIdx)
 8     {
 9         if (srcArr[i] < srcArr[j])
10             tmpArr[k++] = srcArr[i++];
11         else
12             tmpArr[k++] = srcArr[j++];
13     }
14     while (i<=midIdx)
15             tmpArr[k++] = srcArr[i++];
16     while (j<=endIdx)
17             tmpArr[k++] = srcArr[j++];
18     for (int i=startIdx;i<=endIdx;i++)
19         srcArr[i] = tmpArr[i];
20 }
21 
22 void mergeSort(int *srcArr, int *tmpArr, int startIdx, int endIdx)
23 {
24     if (startIdx < endIdx)
25     {
26         int midIdx = (startIdx+endIdx)/2;
27         mergeSort(srcArr, tmpArr, startIdx, midIdx);
28         mergeSort(srcArr, tmpArr, midIdx+1, endIdx);
29         merge(srcArr,tmpArr,startIdx,midIdx,endIdx);
30     }
31 }