算法练习-求和为给定值得两个数

gistfile1.txt

var nums = [1,2,3,6,8,11];
var target = 10;

// 暴力破解法 O(n^2)
function getTwoNumSumBruteForce(nums, target) {
  for (var i = 0; i < nums.length; i++) {
    for (var j = i + 1; j < nums.length; j++) {
      if (nums[i] + nums[j] === target) {
        return [i, j]
      }
    }
  }
  return [-1, -1];
}
console.log('暴力破解法 > ', getTwoNumSumBruteForce(nums, target))

// hash映射法
function getTwoNumSumHashMap(nums, target) {
  var map = {};
  for (var i = 0; i < nums.length; i++) {
    var numNeeded = target - nums[i];
    if (map[numNeeded]) {
      return [map[numNeeded], i]
    }
    map[nums[i]] = i;
  }
  return [-1, -1];
}
console.log('hash映射法 > ', getTwoNumSumHashMap(nums, target))