题意:
给出N,K;
问由K个数字相加得到N的方法有几种;
思路:
问题可以转化成有N个小球放进K个和盒子有几种方法;
#include <cstdio>
#include <cstring>
const int MOD = 1000000;
const int N = 105;
int c[2*N][2*N], n, k;
void getC(int n) {
memset(c, 0, sizeof(c));
c[0][0] = 1;
for(int i = 0; i <= n; i++) {
c[i][0] = c[i][i] = 1;
for(int j = 0; j < i; j++) {
c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % MOD;
}
}
}
int main() {
getC(2*N);
while (scanf("%d%d", &n, &k) && n) {
printf("%d\n", c[n + k - 1][k - 1]);
}
return 0;
}