36 lines
841 B
Kotlin
36 lines
841 B
Kotlin
// version 1.0.6
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fun endsWith89(n: Int): Boolean {
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var digit: Int
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var sum = 0
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var nn = n
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while (true) {
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while (nn > 0) {
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digit = nn % 10
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sum += digit * digit
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nn /= 10
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}
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if (sum == 89) return true
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if (sum == 1) return false
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nn = sum
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sum = 0
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}
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}
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fun main(args: Array<String>) {
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val sums = IntArray(8 * 81 + 1)
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sums[0] = 1
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sums[1] = 0
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var s: Int
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for (n in 1 .. 8)
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for (i in n * 81 downTo 1)
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for (j in 1 .. 9) {
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s = j * j
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if (s > i) break
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sums[i] += sums[i - s]
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}
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var count89 = 0
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for (i in 1 .. 8 * 81)
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if (endsWith89(i)) count89 += sums[i]
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println("There are $count89 numbers from 1 to 100 million ending with 89")
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}
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