【一】twoSum
要求：Given nums = [2, 7, 11, 15], target = 9，Because nums[0] + nums[1] = 2 + 7 = 9, return [0, 1].
複雜度o(n)，運用hashMap。
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<h1>要求：</h1>
<p>Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].</p>
<script type="text/javascript">
function twoSum(arr,target){
var map={};
var lg=arr.length;
if(lg>1){
for(var i=0;i<lg;i++){
var rr=target - arr[i];
if(rr in map){
return ('['+map[rr]+','+i+']');
}
map[arr[i]]=i;
}
return("沒有符合條件的");
}else{
return ("數組長度不夠");
}
}
console.log(twoSum([2,7,8,12],9))
</script>
</body>
</html>