problem-1

readme.md

problem-1

Given nums = [2, 7, 11, 15], target = 18. The output should be [1, 2]. Because nums[1] + nums[2] = 7 + 11 = 18.

Created with <3 with dartpad.dev.

main.dart

import 'dart:math';

void main() {
  //Given nums = [2, 7, 11, 15], target = 18.
  //The output should be [1, 2].
  //Because nums[1] + nums[2] = 7 + 11 = 18.

  final nums = [2, 7, 11, 15];
  int target = 18;

  final result = getResultWay1(nums, target);
  //final result = getResultWay2(nums, target);

  print(result);
}

List<int> getResultWay1(List<int> nums, int target) {
  for (int i = 0; i < nums.length; i++) {
    for (int j = 0; j < nums.length; j++) {
      if (nums[i] + nums[j] == target) {
        return [i, j];
      }
    }
  }
  return [];
}

List<int> getResultWay2(List<int> nums, int target) {
  var map = <int, int>{};

  for (int i = 0; i < nums.length; i++) {
    int complement = target - nums[i];
    if (map.containsKey(complement)) {
      final elem =
          map.entries.firstWhere((element) => element.key == complement);
      return [elem.value, i];
    } else {
      map.putIfAbsent(nums[i], () => i);
    }
  }
  return [];
}