g0301_0400.s0377_combination_sum_iv.Solution.kt Maven / Gradle / Ivy

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Kotlin-based LeetCode algorithm problem solutions, regularly updated

There is a newer version: 1.28

package g0301_0400.s0377_combination_sum_iv

// #Medium #Array #Dynamic_Programming #Dynamic_Programming_I_Day_21
// #2022_11_22_Time_217_ms_(72.41%)_Space_33.9_MB_(86.21%)

class Solution {
    private lateinit var storage: IntArray

    fun combinationSum4(nums: IntArray, target: Int): Int {
        storage = IntArray(target + 1)
        storage.fill(-1)
        return result(nums, target)
    }

    private fun result(nums: IntArray, target: Int): Int {
        if (target < 0) {
            return 0
        }
        if (target == 0) {
            return 1
        }
        if (storage[target] != -1) {
            return storage[target]
        }
        var count = 0
        for (i in nums) {
            count += result(nums, target - i)
        }
        storage[target] = count
        return count
    }
}