Leetcode 322 Coin Change (full backpack)

You is given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins so need to make up that amount. If that amount of cannot is made up by any combination 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 so you have a infinite number of each kind of coin.

Title Link: https://leetcode.com/problems/coin-change/

Title Analysis: Because the number is infinite, so it is a complete knapsack count problem, dp[i] means the minimum number required to close to I, DP initialized to infinity, dp[0] = 0

public class Solution {public
    
    int coinchange (int[] coins, int amount) {
        int[] dp = new Int[amount + 1];
        Arrays.fill (DP, integer.max_value);
        Dp[0] = 0;
        for (int i = 0; i < coins.length; i + +) {for
            (int j = 0; J <= Amount; j + +) {
                int pre = j-coins[i];
                if (pre >= 0 && Dp[pre] < Integer.max_value) {
                    Dp[j] = Math.min (Dp[j], Dp[pre] + 1);}}}
        if (dp[amount] = = integer.max_value) {
            return-1;
        }
        return dp[amount];
    }
}