CF14E题解

当我拿到这个题，心里一想：这是紫题，一定不简单啊！

直到我看到了数据范围。

$3\leq n\leq 20,1\leq t\leq 10$

难道……我可以打表？

事实证明完全可以。

在我辛辛苦苦手写2小时之后，这个表终于诞生了！

{{0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0},{0,14,0,0,0,0,0,0,0,0,0},{0,22,0,0,0,0,0,0,0,0,0},{0,16,70,0,0,0,0,0,0,0,0},{0,6,232,0,0,0,0,0,0,0,0},{0,1,380,？,0,0,0,0,0,0,0},{0,0,396,1786,0,0,0,0,0,0,0},{0,0,284,4500,1782,0,0,0,0,0,0},{0,0,142,7414,12122,0,0,0,0,0,0},{0,0,48,8849,？,8997,0,0,0,0,0},{0,0,10,8028,92226,76878,0,0,0,0,0},{0,0,1,5658,152140,328222,45425,0,0,0,0},{0,0,0,3112,195420,928494,467292,0,0,0,0},{0,0,0,1322,201744,1947581,2402980,229347,0,0,0},{0,0,0,422,？,？,8205152,2758896,0,0,0},{0,0,0,96,118912,4322956,20852648,16954160,？,0,0},{0,0,0,14,68640,4846524,41920210,66357900,15946870,0,0},{0,0,0,？,？,？,？,197939352,109824208,5846414,0},{0,0,0,0,12628,3715462,？,468541040,503245466,90700276,0}}

（为防止CTJ，将表盖住一块）

没错就这么点

然后我再补一下代码：

#include<iostream>\
using namespace std;
long long a[21][11]= {{0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0},{0,0,0,0,0,0,0,0,0,0,0},{0,14,0,0,0,0,0,0,0,0,0},{0,22,0,0,0,0,0,0,0,0,0},{0,16,70,0,0,0,0,0,0,0,0},{0,6,232,0,0,0,0,0,0,0,0},{0,1,380,353,0,0,0,0,0,0,0},{0,0,396,1786,0,0,0,0,0,0,0},{0,0,284,4500,1782,0,0,0,0,0,0},{0,0,142,7414,12122,0,0,0,0,0,0},{0,0,48,8849,41160,8997,0,0,0,0,0},{0,0,10,8028,92226,76878,0,0,0,0,0},{0,0,1,5658,152140,328222,45425,0,0,0,0},{0,0,0,3112,195420,928494,467292,0,0,0,0},{0,0,0,1322,201744,1947581,2402980,229347,0,0,0},{0,0,0,422,170444,3213988,8205152,2758896,0,0,0},{0,0,0,96,118912,4322956,20852648,16954160,1197954,0,0},{0,0,0,14,68640,4846524,41920210,66357900,15946870,0,0},{0,0,0,1,32632,4594423,69183464,197939352,109824208,5846414,0},{0,0,0,0,12628,3715462,96046590,468541040,503245466,90700276,0}}
int main(){
	int n,t;
	cin>>n>>t;
	cout<<a[n][t]<<endl;
	return 0;
}