public static int coinChange(int [] coins,int amount){
    if (amount == 0){
        return 0;
    }
    if (coins == null || coins.length <= 0){
            return -1;
    }
    int [] dp = new int[amount +1];
    Arrays.fill(dp,amount +1);
    dp[0] = 0;
    for (int i = 1; i <= amount;i++){
        for (int j = 0;j < coins.length;j++){
            // 过滤掉面值比总额还大的
            if (coins[j] <= i){
                dp[i] = Math.min(dp[i],dp[i-coins[j]] +1);
            }
        }
    }
    return dp[amount] > amount ? -1:dp[amount];
        
}