Package g0601_0700.s0677_map_sum_pairs

Class MapSum

java.lang.Object

g0601_0700.s0677_map_sum_pairs.MapSum

public class MapSum
extends Object

677 - Map Sum Pairs\. Medium 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:** **Input** ["MapSum", "insert", "sum", "insert", "sum"] [ [], ["apple", 3], ["ap"], ["app", 2], ["ap"]] **Output:** [null, null, 3, null, 5] **Explanation:** MapSum mapSum = new MapSum(); mapSum.insert("apple", 3); mapSum.sum("ap"); // return 3 (apple = 3) mapSum.insert("app", 2); mapSum.sum("ap"); // return 5 (apple + app = 3 + 2 = 5) **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`.

Constructor Summary

Constructors

Constructor	Description
MapSum()

Method Summary

Modifier and Type	Method	Description
void	insert(String key, int val)
int	sum(String prefix)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MapSum

public MapSum()

Method Details

insert

public void insert(String key,
 int val)

sum

public int sum(String prefix)