public static int coinChnage(int[]c, int n) {
		int[] dp=new int[n+1];
		dp[0]=1;
		for (int i=0;i<c.length;++i)
			for (int j=1;j<=n;++j)
				if (j-c[i]>=0)
					dp[j]+=dp[j-c[i]];
		return dp[n];
	}