排序

快速排序

void QuickSort(int arr[],int left,int right){
    if(right<=left) return;
    int i=left; int j=right;
    int key=arr[(i+j)/2];
    while(i<=j){
        while(arr[i]<key){
            i++;
            if(i==right){
                break;
            }
        }
        while(arr[j]>key){
            j--;
            if(j==left){
                break;
            }
        }
        if(i<=j){
            swap(arr[i],arr[j]);
            i++;j--;
        }
    }
    QuickSort(arr,left,j);
    QuickSort(arr,i,right);
}

归并排序

void mergesort(int arr[],int s,int t,int temp[]){
    if(s>=t) return;
    int mid=(s+t)>>1;
    mergesort(arr,s,mid,temp);
    mergesort(arr,mid+1,t,temp);
    int i=s; int j=mid+1; int k=s;
    while(i<=mid&&j<=t){
        if(arr[i]<=arr[j]) temp[k++]=arr[i++];
        else temp[k++]=arr[j++];
    }
    while(i<=mid) temp[k++]=arr[i]++;
    while(j<=t) temp[k++]=arr[j++];
    for(int l=s;l<=t;l++) arr[l]=temp[l];
}