677. Map Sum Pairs
Medium
Last updated
Medium
Last updated
Design a map that allows you to do the following:
Maps a string key to a given value.
Returns the sum of the values that have a key with a prefix equal to a given string.
Implement the MapSum
class:
MapSum()
Initializes the MapSum
object.
void insert(String key, int val)
Inserts the key-val
pair into the map. If the key
already existed, the original key-value
pair will be overridden to the new one.
int sum(string prefix)
Returns the sum of all the pairs' value whose key
starts with the prefix
.
Example 1:
Constraints:
1 <= key.length, prefix.length <= 50
key
and prefix
consist of only lowercase English letters.
1 <= val <= 1000
At most 50
calls will be made to insert
and sum
.
加總的時候利用 queue 的技巧。
Runtime: 0 ms, faster than 100%
Memory Usage: 2.9 MB, less than 34.78%