学习逆序数,用这道题来练习归并排序。
#include <stdlib.h> #include <stdio.h> #include <string.h> // merge sort int num[101]; void merge(int num[], int left, int mid, int right) { int i = left, j = mid + 1, k = left; int temp[101]; while (i <= mid && j <= right) { if (abs(num[i]) > abs(num[j])) { temp[k++] = num[i++]; } else { temp[k++] = num[j++]; } } if (i > mid) { while (j <= right) temp[k++] = num[j++]; } else { while (i <= mid) temp[k++] = num[i++]; } for (i = left; i <= right; i++) num[i] = temp[i]; } void mergeSort(int num[], int left, int right) { if (left < right) { int mid = (left + right) / 2; mergeSort(num, left, mid); mergeSort(num, mid + 1, right); merge(num, left, mid, right); } } int main() { int n, i; while (1) { scanf("%d", &n); if (!n) break; for (i = 1; i <= n; i++) scanf("%d", &num[i]); mergeSort(num, 1, n); for (i = 1; i <= n; i++) { printf("%d", num[i]); if (i < n) printf(" "); else printf("\n"); } } return 0; }