摘要： /*POJ1240Pre-Post-erous*/#include <iostream>#include <cstring>#include<cstdio>using namespace std;char pre[30],post[30];int num;int C(int n, int k) //计算组合数C(n, k){ int i, sum= 1; if (k>(n>>2)) k = n - k; for (i = 1; i <= k; ++i) sum=sum*(n - i + 1) / i; return... 阅读全文