计数排序

 1 #include <iostream>
 2 using namespace std;
 3 const int MAXN = 100000;
 4 const int k = 1000; // range
 5 int a[MAXN], c[MAXN], ranked[MAXN];
 6  
 7 int main() {
 8     int n;
 9     cin >> n;
10     for (int i = 0; i < n; ++i) {
11         cin >> a[i]; 
12         ++c[a[i]];
13     }
14     for (int i = 1; i < k; ++i)
15         c[i] += c[i-1];
16     for (int i = n-1; i >= 0; --i)
17         ranked[--c[a[i]]] = a[i];//如果是i表达的是原数标号，a[i]就是排序后的正确序列
18     for (int i = 0; i < n; ++i)
19         cout << ranked[i] << endl;
20     return 0;
21 }