uva 10721 - Bar Codes(dp)

题目链接：uva 10721 - Bar Codes

题目大意：给出n，k和m，用k个1~m的数组成n，问有几种组成方法。

解题思路：简单dp，cnt[i][j]表示用i个数组成j， cnt[i][j] = ∑(1 ≤ t  ≤min(k, j)) cnt[i - 1][t].

 

#include <stdio.h>

#include <string.h>

#define ll long long

const int N = 105;



ll cnt[N][N];

int n, k, m;



void init() {

	memset(cnt, 0, sizeof(cnt));

	cnt[0][0] = 1;

}



void solve() {

	init();

	for (int i = 1; i <= k; i++) {

		for (int j = 1; j <= n; j++) {

			for (int t = 1;  t <= m && t <= j; t++)

				cnt[i][j] += cnt[i - 1][j - t];

		}

	}	

	printf("%lld\n", cnt[k][n]);

}



int main () {

	while (scanf("%d%d%d", &n, &k, &m) == 3) {

		solve();

	}

	return 0;

}