public int coinChange(int[] coins, int amount) {

Arrays.sort(coins);

int[] dp = new int[amount + 1];

Arrays.fill(dp, -1);

dp[0] = 0;

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

for (int coin: coins) {

if (i - coin >= 0 && dp[i - coin] >= 0) {

int k = dp[i - coin] + 1;

dp[i] = dp[i] > 0 ? Math.min(dp[i], k) : k;

}

}

}

return dp[amount];

}