uva10943 How do you add?

题意：把K个不超过N的非负整数加起来，使得它们的和为N，有多少种方法

思路：令dp[i][j]为和为i用了j个数的方案数，那么转移就是dp[i][j]=dp[i-1][j]+dp[i][j-1]

#include<bits/stdc++.h>using namespace std;int dp[101][101];const int mod = 1e6;int main(){for (int i = 1;i<=100;i++){dp[i][1]=1;dp[1][i]=i;}for (int i = 2;i<=100;i++)for (int j = 2;j<=100;j++)dp[i][j]=(dp[i-1][j]+dp[i][j-1])%mod;int n,k;while (scanf("%d%d",&n,&k)!=EOF && n+k){         printf("%d\n",dp[n][k]);} }