题目传送门:http://www.lydsy.com/JudgeOnline/problem.php?id=1211
数据生成器:http://paste.ubuntu.com/23338142/
这题知道prufer编码的人做起来是大水题吧?
可以搞一搞组合数,或者直接上可重集的全排列?
#include<bits/stdc++.h> #define LL long long using namespace std; inline int read(){ char c=getchar(); int ret=0,f=1; while (c<'0'||c>'9') {if(c=='-')f=-1;c=getchar();} while (c<='9'&&c>='0') {ret=ret*10+c-'0';c=getchar();} return ret*f; } inline int C(const int &a, const int &b) { static int ret; ret = 1; for (int i=1;i<=b;i++) ret *= i; for (int i=1;i<=a;i++) ret /= i; for (int i=1;i<=b-a;i++) ret /= i; return ret; } int main(){ int n=read(); if (n == 1) { if (read() == 0) puts("1"); else puts("0"); } else if (n == 2) { if (read() == 1 && read() == 1) puts("1"); else puts("0"); } else { n -= 2; LL vout = 1; for (int i=n+2,tmp;i;i--) { vout *= C(tmp=read()-1,n); n -= tmp; } if (n == 0) cout<<vout; else puts("0"); } return 0; }
Hey there just wanted to give you a quick heads up and let you know a few of the images aren’t loading correctly. I’m not sure why but I think its a linking issue. I’ve tried it in two different internet browsers and both show the same results.
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