leet322：零钱兑换

public static int coinChange(int[] coins, int amount) {
    // 动态规划
    int[] memo = new int[amount + 1];
    Arrays.fill(memo, amount + 1);
    memo[0] = 0;
    for (int i = 1; i <= amount; i++) {
        for (int coin : coins) {
            if (i - coin >= 0) {
                memo[i] = Math.min(memo[i], memo[i - coin] + 1);
            }
        }
    }
    return memo[amount] == amount + 1 ? -1 : memo[amount];
}

public static int coinChange1(int[] coins, int amount) {
        int [] f = new int[amount + 1];
        f[0] = 0;

        for(int i = 1; i <= amount; i++){
            int cost = Integer.MAX_VALUE;
            for(int j = 0; j < coins.length; j++){
                if(i - coins[j] >= 0){
                    if(f[i-coins[j]] != Integer.MAX_VALUE)
                        cost = Math.min(cost, f[i - coins[j]] + 1);
                }
            }
            f[i] = cost;
        }
        return  f[amount] == Integer.MAX_VALUE? -1 : f[amount];

}