算法导论代码笔记(一)
插入排序int i,key;
for(i=1;i=0&&a[j]>key;--j)
{
a[j+1] = a[j];
}
a[j+1] = key;
}
int key;
for(int i=0;i a[j])
{
int temp = a[j];
a[j] = a[i];
a[i] = temp;
}
}
} 冒泡排序
for(int i=0;i=1;--j)
{
if(a[j] 归并排序
int b1[1000];
int b2[1000];
void Merge(int *p, int l, int h1, int h2)
{
int k = 0,n1 = h1 - l + 1,n2 = h2 - h1;
for (int i = l; i <= h1; ++i)
b1[k++] = p[i];
b1[n1] = MAX_INT;
k = 0;
for (int i = h1 + 1; i <= h2; ++i)
b2[k++] = p[i];
b2[n2] = MAX_INT;
k = l;
for (int i = 0, j = 0; k<=h2;++k)
{
if (b1[i] < b2[j])
p[k] = b1[i++];
else
p[k] = b2[j++];
}
}
void merge_sort(int *p, int l, int h)
{
if (l < h)
{
int n = (h + l) / 2;
merge_sort(p, l, n);
merge_sort(p, n + 1, h);
Merge(p, l, n, h);
}
}int Merge(int *p, int l, int h1, int h2)
{
int ans = 0;
int k = 0,n1 = h1 - l + 1,n2 = h2 - h1;
for (int i = l; i <= h1; ++i)
b1[k++] = p[i];
b1[n1] = MAX_INT;
k = 0;
for (int i = h1 + 1; i <= h2; ++i)
b2[k++] = p[i];
b2[n2] = MAX_INT;
k = l;
for (int i = 0, j = 0; k<=h2;++k)
{
if (b1[i] <= b2[j])
p[k] = b1[i++];
else
{
p[k] = b2[j++];
ans += n1 - i;
}
}
return ans;
}
int merge_sort(int *p, int l, int h)
{
int ans = 0;
if (l < h)
{
int n = (h + l) / 2;
ans += merge_sort(p, l, n) + merge_sort(p, n + 1, h);
ans += Merge(p, l, n, h);
}
return ans;
}快速排序
void quick_sort(int *a,int l,int h)
{
if(l < h)
{
int x = l,temp;
int i=x+1,j=x+1;
for(;i<=h;++i)
{
if(a[i] < a[x])
{
temp = a[j];
a[j++] = a[i];
a[i] = temp;
}
}
temp = a[j-1];
a[j-1] = a[x];
a[x] = temp;
quick_sort(a,l,j-1);
quick_sort(a,j,h);
}
}int Rand(int l,int h)
{
srand(time(NULL));
return (rand()%(h-l+1))+l;
}
void Swap(int *a,int *b)
{
int temp = *a;
*a = *b;
*b = temp;
}
void quick_sort(int *a,int l,int h)
{
if(l < h)
{
int x = Rand(l,h);
Swap(&a[x],&a[l]);
int i=l+1,j=l+1;
for(;i<=h;++i)
{
if(a[i] < a[l])
{
Swap(&a[i],&a[j]);
++j;
}
}
Swap(&a[j-1],&a[l]);
quick_sort(a,l,j-1);
quick_sort(a,j,h);
}
}
堆排序
#include
#include
void swap (int *a,int *b)
{
int temp = *a;
*a = *b;
*b = temp;
}
MinHeapFixDown(int *a,int i,int n)
{
int j,temp;
temp = a[i];
j = 2 * i + 1;
while(j < n)
{
if(j + 1 < n && a[j+1] < a[j])
++j;
if(a[j] >= temp)
break;
a[i] = a[j];
i = j;
j = 2 * i + 1;
}
a[i] = temp;
}
MinHeapFixUp(int *a,int i,int n)
{
int temp = a[i],j = 2*i+1;
while(j < n)
{
if(j + 1 < n &&a[j+1] > a[j])
++j;
if(a[j] <= temp)
break;
a[i] = a[j];
i = j;
j = 2 * i + 1;
}
a[i] = temp;
}
BuildMinHeap (int *a,int n)
{
int i;
for(i = (n / 2) - 1;i>=0;--i)
{
MinHeapFixDown(a,i,n);
}
}
BuildMaxHeap(int *a,int n)
{
int i = (n / 2) - 1;
for(;i>=0;--i)
MinHeapFixUp(a,i,n);
}
DownHeapSort(int *a,int n)
{
int i;
BuildMinHeap (a,n);
for(i = n-1;i>=0;--i)
{
swap(&a[i],&a[0]);
MinHeapFixDown(a,0,i);
}
}
UpHeapSort(int *a,int n)
{
BuildMaxHeap(a,n);
int i = n-1;
for(;i>=0;--i)
{
swap(&a[0],&a[i]);
MinHeapFixUp(a,0,i);
}
}
int main()
{
int a[10] = {32,324,23,24,235,4,34,45,32,36};
UpHeapSort(a,10);
int i;
for(i = 0;i<10;++i)
printf("%d ",a[i]);
return 0;
}
计数排序
int a[] = {100,4,2,5,5,6,22,325,666,4};
int b[10];
int c[1000];
void count_sort(int *a,int *b,int l,int h)
{
memset(c,0,sizeof(c));
int k = -1;
for(int i=l;i<=h;++i)
{
k = (k>=a[i]?k:a[i]);
++c[a[i]];
}
for(int i=1;i<=k;++i)
{
c[i] = c[i-1] + c[i];
}
for(int i=h;i>=l;--i)
{
b[--c[a[i]]] = a[i];
}
}int a[] = {0x0fff,0x0f0f,0x0ff0,0x000f,0x00ff,0x0f0f,0x00f0,0xffff,0x0000,0x00ff};
int c[256];
void count_sort(int basic,int off,int *a,int *b,int l,int h)
{
memset(c,0,sizeof(c));
int k = -1,t;
for(int i=l;i<=h;++i)
{
t = (a[i]&basic)>>(4*off);
//printf("basic:%x t:%x\n",basic,t);
k = (k>=t?k:t);
++c[t];
}
for(int i=1;i<=k;++i)
{
c[i] = c[i-1] + c[i];
}
for(int i=h;i>=l;--i)
{
t = (a[i]&basic)>>(4*off);
b[--c[t]] = a[i];
}
}
//数组初始化为16位 bits=16
void basic_sort(int bits,int *a,int l,int h)
{
int times = bits / 4;
int **b = (int**)malloc(times * sizeof(int*));
for(int i=0;i查找第i小
int Rand(int l,int h)
{
srand(time(NULL));
return (rand()%(h-l+1))+l;
}
void Swap(int *a,int *b)
{
int temp = *a;
*a = *b;
*b = temp;
}
int random_select(int *a,int l,int h,int f)
{
if(l < h)
{
int x = Rand(l,h);
Swap(&a[x],&a[l]);
int i=l+1,j=l+1;
for(;i<=h;++i)
{
if(a[i] < a[l])
{
Swap(&a[i],&a[j]);
++j;
}
}
Swap(&a[j-1],&a[l]);
cout<<"tt"<