[英]Number of ways to give coin change
我正在尝试使用记忆和递归来解决硬币找零问题。 但是我的代码中有一些小故障,它给了我错误的输出。
public static int coinChangeMemo(int coins[], int n) {
int [][] memo = new int[n+1][coins.length+1];
for (int row = 0; row < memo.length; row++) {
for (int col = 0; col < memo[row].length; col++) {
memo[row][col] =-1;
}
}
return coinChangeMemoHelper(coins, n, 0, memo);
}
private static int coinChangeMemoHelper(int coins[], int n, int index, int memo[][]) {
if(n == 0) {
return 1;
}
if(index >= coins.length) {
return 0;
}
if(n <= 0) {
return 0;
}
if(memo[n][index] != -1) {
return memo[n][index];
}
int withUsingCurrent = coinChangeMemoHelper(coins, n-coins[0], index, memo);
int withoutUsingCurrent = coinChangeMemoHelper(coins, n, index+1, memo);
memo[n][index] = withUsingCurrent + withoutUsingCurrent;
return withUsingCurrent + withoutUsingCurrent;
}
public static void main(String[] args) {
//coins denominations are 1, 2
int coins[] = {1,2};
//i want a change of 4
int sum = 4;
System.out.println(coinChangeMemo(coins, sum));
硬币面额可用 1,2
我想要总数为 4。
可能的方法是
我期待输出 3,但它返回给我 5
您需要对代码进行 2 处更改:-> 1.您可以将最后 2 个基本情况组合为: if(index==coins.length || n<0){ return 0; 2. 你在递归调用 withUsingCurrent 时犯了错误: UPDATE IT LIKE THIS BELOW int withUsingCurrent = coinChangeMemoHelper(coins, n-coins[index], index, memo);
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