322. Change of change-the minimum number of coins required to make up the total amount

Given coins of different denominations  coins and a total amount  amount. Write a function to calculate the minimum number of coins required to make up the total amount. If none of the coin combinations can make up the total amount, return  -1.

You can think that the number of each coin is unlimited.

 

Example 1:

Input: coins = [1, 2, 5], amount = 11
Output: 3 
explanation: 11 = 5 + 5 + 1

Example 2:

Input: coins = [2], amount = 3
output: -1

Example 3:

输入：coins = [1], amount = 0
输出：0

Example 4:

输入：coins = [1], amount = 1
输出：1

Example 5:

输入：coins = [1], amount = 2
输出：2

 

prompt:

• 1 <= coins.length <= 12
• 1 <= coins[i] <= 231 - 1
• 0 <= amount <= 104

package Solution322;

public class Solution {

	public int coinChange(int[] coins, int amount) {
		int dp[] = new int[amount + 1];
		dp[0] = 0;
		for (int i = 1; i <= amount; i++) {
			dp[i] = amount + 1;
		}
		for (int coin : coins) {
			for (int amt = 1; amt <= amount; amt++) {
				if (amt >= coin) {
					dp[amt] = Math.min(dp[amt], 1 + dp[amt - coin]);
				}
			}
		}
		int minCoinsReq = dp[amount] != amount + 1 ? dp[amount] : -1;
		return minCoinsReq;
	}

	public static void main(String[] args) {

		Solution sol = new Solution();

		int[] coins = { 1, 2, 5 };
		int amount = 11;

		System.out.println(sol.coinChange(coins, amount));
	}

}

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