qq.kt

// Simple

fun arrayManipulation(n: Int, queries: Array<Array<Int>>): Long {
    val checkpoints = Array<Long>(n, { 0 })
    for ((start, end, value) in queries) {
        checkpoints[start - 1] += value.toLong()
        if (end < n) {
            checkpoints[end] -= value.toLong()
        }
    }
    var accumulated_sum: Long = 0;
    var max: Long = 0;
    for (checkpoint in checkpoints) {
        accumulated_sum += checkpoint
        if (accumulated_sum > max) {
            max = accumulated_sum
        }
    }
    return max
}


// Overkill

data class CheckpointFold(var max_value: Long, var accumulated_value: Long)

operator fun CheckpointFold.plusAssign(value: Long) {
    this.accumulated_value += value
    if (this.max_value < this.accumulated_value) {
        this.max_value = this.accumulated_value
    }
}

// Complete the arrayManipulation function below.
fun arrayManipulation(n: Int, queries: Array<Array<Int>>): Long {
    val checkpoints = Array<Long>(n, { 0 })
    for ((start, end, value) in queries) {
        checkpoints[start - 1] += value.toLong()
        if (end < n) {
            checkpoints[end] -= value.toLong()
        }
    }
    return checkpoints.fold(
        CheckpointFold(0, 0),
        { checkpoint_fold, checkpoint ->
            checkpoint_fold += checkpoint
            checkpoint_fold
        }
    ).max_value
}