Coin Change

Source

• leetcode: Coin Change

You are given coins of different denominations and a total amount of money
amount. Write a function to compute the fewest number of coins that you need
to make up that amount. If that amount of money cannot be made up by
anycombination of the coins, return -1.

Example 1:
coins = [1, 2, 5], amount = 11
return 3 (11 = 5 + 5 + 1)

Example 2:
coins = [2], amount = 3
return -1.

Note:
You may assume that you have an infinite number of each kind of coin.

Java

public class Solution {
    public int coinChange(int[] coins, int amount) {
        if (coins == null || coins.length == 0)
            return -1;

        if (amount <= 0)
            return 0;

        int dp[] = new int[amount + 1];
        for (int i = 1; i < dp.length; i++) {
            dp[i] = Integer.MAX_VALUE;
        }

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