33 lines
1.0 KiB
Java
33 lines
1.0 KiB
Java
public class DammAlgorithm {
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private static final int[][] table = {
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{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
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{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
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{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
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{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
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{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
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{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
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{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
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{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
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{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
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{2, 5, 8, 1, 4, 3, 6, 7, 9, 0},
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};
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private static boolean damm(String s) {
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int interim = 0;
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for (char c : s.toCharArray()) interim = table[interim][c - '0'];
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return interim == 0;
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}
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public static void main(String[] args) {
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int[] numbers = {5724, 5727, 112946, 112949};
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for (Integer number : numbers) {
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boolean isValid = damm(number.toString());
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if (isValid) {
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System.out.printf("%6d is valid\n", number);
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} else {
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System.out.printf("%6d is invalid\n", number);
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}
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}
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}
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}
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