Problema
Programs often receive JSON such as {"apples": 3, "pears": 5}. Libraries like System.Text.Json parse it for you, but parsing a simple case by hand shows how the format works.
The input is a flat JSON object: {, then zero or more "key": value pairs separated by commas, then }. Keys are quoted and contain no quotes, commas or colons; values are integers, possibly negative. Spaces may appear around any of the symbols.
Implement sum_json_numbers(text).
Input
text: The JSON object.
Output
Return the sum of all values (0 for an empty object).
Vincoli
2 ≤ length of text ≤ 100,000
At most 10,000 pairs; every value and the sum fit in a 64-bit integer
Esempi
Input:
text = "{\"apples\": 3, \"pears\": 5}"
Output atteso:
expected = 8Input:
std::string text = "{\"apples\": 3, \"pears\": 5}";
Output atteso:
long long expected = 8;Input:
string text = "{\"apples\": 3, \"pears\": 5}";
Output atteso:
long expected = 8;Spiegazione
3 + 5 = 8.
Input:
text = "{ \"debt\" : -20 , \"cash\":15 }"
Output atteso:
expected = -5Input:
std::string text = "{ \"debt\" : -20 , \"cash\":15 }";
Output atteso:
long long expected = -5;Input:
string text = "{ \"debt\" : -20 , \"cash\":15 }";
Output atteso:
long expected = -5;Spiegazione
Spaces around the symbols do not matter: −20 + 15 = −5.
Come affrontarlo
Prova prima da solo, poi apri un suggerimento alla volta.
Suggerimento 1
Remove the braces, then split the pairs at commas.
Suggerimento 2
Each value is the text after the colon; trim spaces before converting.
Suggerimento 3
Use a 64-bit integer and return 0 for an empty object.
Complessità attesa
O(length of text) time, O(1) extra space
Riferimenti
Questa sfida è adattata per CodeUtility. Segui la traccia e i vincoli sopra.