SDUT2883 hearthstone//stirling

Fifth session of the provincial race: Hearthstone

Combinatorial mathematics.

n Races, M tables (n>=m). Each race is a table, and each table is used at least once.

The idea behind the question has been how to fill the M table with n positions.

is actually the Tao Stirling number model, the direct set formula M!*{n m}

#include <stdio.h>#include<string.h>#defineL 1000000007intMain () {intn,m; Long Longa[101];  while(SCANF ("%d%d", &n,&m)! =EOF) {a[0]=0;  for(intI=1; i<=n;i++) A[i]=1;  for(intI=3; i<=n;i++)             for(intj=i-1;j>0; j--) A[j]= (j*a[j]%l+a[j-1])%m;  for(intI=1; i<=m;i++) A[m]= ((a[m]%l) *i)%L; printf ("%lld\n", A[m]); }    return 1;}

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Not at first, then the array is opened to a long long on the line >_<

SDUT2883 hearthstone//stirling