```
public int coinChange(int[] coins, int amount) {
if(coins == null || amount < 0)
return -1;
if(amount == 0)
return 0;
int[] dp = new int[amount+1];
for(int i = 1; i <=amount; i++){
int min = Integer.MAX_VALUE;
for(int j = 0; j < coins.length; j++){
if(i >= coins[j] && dp[i - coins[j]] != -1)
min = Math.min(min, 1 + dp[i - coins[j]]);
}
dp[i] = min == Integer.MAX_VALUE ? -1 : min;
}
return dp[amount];
}
```