递推法计算组合数

NegativeElves · Nov 27, 2016 · 4a61aad · 4a61aad
1 parent fcdbb41
commit 4a61aad
Showing 1 changed file with 32 additions and 0 deletions.
diff --git a/Combination(Recursion).cpp b/Combination(Recursion).cpp
@@ -0,0 +1,32 @@
+#include <cstdio>
+
+#define MOD 1000000000
+#define MAX 1000
+
+int C[MAX][MAX];
+
+void init_C()
+{
+	for (int i = 0; i < MAX; i++)
+	{
+		C[i][0] = 1;
+	}
+	for (int i = 1; i < MAX; i++)
+	{
+		for (int j = 1; j <= i; j++)
+		{
+			C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % MOD;
+		}
+	}
+}
+
+int main()
+{
+	int n, m;
+	init_C();
+	while (scanf("%d%d", &n, &m) > 0)
+	{
+		printf("%d\n", C[n][m]);
+	}
+	return 0;
+}