算法导论2.3算法设计分治法合并排序

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// 2.3.1 merge.h #include <stdint.h> // MERGE(A, p, q, r) // n1 = q - p + 1 // n2 = r - q // let L[1..n1 + 1] and R[1..n2 + 1] be new arrays // for i = 1 to n1 //     L[i] = A[p + i - 1] // for j = 1 to n2 //     R[j] = A[q + j] // L[n1 + 1] = INT64_MAX // R[n2 + 1] = INT64_MAX // i = 1 // j = 1 // for k = p to r //     if L[i] <= R[j] //         A[k] = L[i] //         i = i + 1 //     else A[k] = R[j] //         j = j + 1   void merge(int64_t* A, uint64_t p, uint64_t q, uint64_t r) {     uint64_t n1 = q - p + 1;     uint64_t n2 = r - q;     int64_t* L = new int64_t[n1 * sizeof(int64_t)];     int64_t* R = new int64_t[n2 * sizeof(int64_t)];     for (uint64_t i = 0; i < n1; i++)     {         L[i] = A[p + i];     }     for (uint64_t j = 0; j < n2; j++)     {         R[j] = A[q + j + 1];     }     L[n1] = INT64_MAX;     R[n2] = INT64_MAX;     uint64_t i = 0;     uint64_t j = 0;     for (uint64_t k = p; k < r + 1; k++)     {         if (L[i] <= R[j])         {             A[k] = L[i];             i++;         }         else         {             A[k] = R[j];             j++;         }     } }   // MERGE-SORT(A, p, r) // if p < r //     q = |_(p + r) / 2_| //     MERGE-SORT(A, p, q) //     MERGE-SORT(A, q + 1, r) //     MERGE(A, p, q, r)   void merge_sort(int64_t* A, uint64_t p, uint64_t r) {     if (p < r)     {         uint64_t q = (p + r) / 2;         merge_sort(A, p, q);         merge_sort(A, q + 1, r);         merge(A, p, q, r);     } }   // 2.3.1 merge.cpp #include <iostream>   #ifdef __linux #include <stdio.h> #endif   #include "merge.h"   using std::cout; using std::cin; using std::endl;   int main() { #if __WORDSIZE == 64     std::cout << "WORD_SIZE == 64" << std::endl; #endif     int const n(10);     int64_t a[n] = { 9, 1, 3, 10, 7, -3, 4, 2, 5, 0 };       merge_sort(a, 0, n - 1);     cout << "The sorted array is" << endl;     for(int i = 0; i < n; i++)         cout << a[i] << " ";     cout << endl;       getchar();     return 0; }

 

合并排序模版

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// merge_t.h #include <stdint.h> // MERGE(A, p, q, r) // n1 = q - p + 1 // n2 = r - q // let L[1..n1 + 1] and R[1..n2 + 1] be new arrays // for i = 1 to n1 //     L[i] = A[p + i - 1] // for j = 1 to n2 //     R[j] = A[q + j] // L[n1 + 1] = INT64_MAX // R[n2 + 1] = INT64_MAX // i = 1 // j = 1 // for k = p to r //     if L[i] <= R[j] //         A[k] = L[i] //         i = i + 1 //     else A[k] = R[j] //         j = j + 1   template <class TYPE> void merge_t(TYPE* A, uint64_t p, uint64_t q, uint64_t r) {     uint64_t n1 = q - p + 1;     uint64_t n2 = r - q;     TYPE* L = new TYPE[n1 * sizeof(TYPE)];     TYPE* R = new TYPE[n2 * sizeof(TYPE)];     for (uint64_t i = 0; i < n1; i++)     {         L[i] = A[p + i];     }     for (uint64_t j = 0; j < n2; j++)     {         R[j] = A[q + j + 1];     }     L[n1] = INT64_MAX;     R[n2] = INT64_MAX;     uint64_t i = 0;     uint64_t j = 0;     for (uint64_t k = p; k < r + 1; k++)     {         if (L[i] <= R[j])         {             A[k] = L[i];             i++;         }         else         {             A[k] = R[j];             j++;         }     } }   // MERGE-SORT(A, p, r) // if p < r //     q = |_(p + r) / 2_| //     MERGE-SORT(A, p, q) //     MERGE-SORT(A, q + 1, r) //     MERGE(A, p, q, r)   template <class TYPE> void merge_sort_t(TYPE* A, uint64_t p, uint64_t r) {     if (p < r)     {         uint64_t q = (p + r) / 2;         merge_sort_t(A, p, q);         merge_sort_t(A, q + 1, r);         merge_t(A, p, q, r);     } }   // merge_t.cpp #include <iostream>   #include "merge_t.h"   using std::cout; using std::cin; using std::endl;   int main() {     int const n(10);     int64_t a[n] = { 9, 1, 3, 10, 7, -3, 4, 2, 5, 0 };       merge_sort_t(a, 0, n - 1);     cout << "The sorted array is" << endl;     for(int i = 0; i < n; i++)         cout << a[i] << " ";     cout << endl;       getchar();     return 0; }