分析：
考察归并排序，用简单的快排会超时。
1 #include <iostream> 2 #include <stdio.h> 3 #include <algorithm> 4 #include <cstring> 5 #include <string> 6 #include <vector> 7 #include <cctype> 8 #include <stack> 9 #include <map> 10 11 using namespace std; 12 13 // 归并排序 14 15 int a[1000005]; 16 int b[1000005]; 17 int c[2000005]; 18 19 int merge(int n, int m) 20 { 21 int i = 0, j = 0, k = 0; 22 while (i < n && j < m) 23 { 24 if (a[i] > b[j]) 25 c[k++] = b[j], j++; 26 else 27 c[k++] = a[i], i++; 28 } 29 while (i < n) 30 c[k++] = a[i], i++; 31 while (j < m) 32 c[k++] = b[j], j++; 33 return k; 34 } 35 36 int main() 37 { 38 int n, m; 39 while (scanf("%d", &n) != EOF) 40 { 41 for (int i = 0; i < n; i++) 42 scanf("%d", &a[i]); 43 44 scanf("%d", &m); 45 for (int i = 0; i < m; i++) 46 scanf("%d", &b[i]); 47 48 int l = merge(n, m); 49 50 if (l % 2 == 1) 51 printf("%d\n", c[l >> 1]); 52 else 53 printf("%d\n", c[(l - 1) >> 1]); 54 } 55 return 0; 56 }
