求两数之和 #14

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1. CodeRookie262

   added

   算法

   on Jan 4, 2021
2. CodeRookie262 commented on Jan 5, 2021

   

   CodeRookie262

   on Jan 5, 2021

   OwnerAuthor

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   暴力破解法（循环嵌套）

   function twoSum(arr, target) {
     for (var i = 0, len = arr.length; i < len; i++) {
       for (var j = i + 1; j < len; j++) {
         if (arr[i] + arr[j] === target) return [i, j];
       }
     }
   }

   哈希表标记

   function twoSum(arr, target) {
     let memo = {};
   
     for (var i = 0; i < arr.length; i++) {
       if (memo[target - arr[i]] === undefined) {
         memo[arr[i]] = i;
       }
       if (memo[target - arr[i]] !== undefined && memo[target - arr[i]] !== i)
         return [memo[target - arr[i]], i];
     }
   }