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Is it O(n) or O(1) (by saving the length in a private variable during string allocation to the object)?
if it is O(n), does it mean that the complexity of following code is O(n^2)?
for(int i=0; i<s.length()-1;i++){
//some code here!
}
437
The complexity is O(1) Since String class have the length as a field .
Java String length() Method The length() method returns the length of a specified string.
Either the String class keeps the string's length in a variable. In that case this variable is just returned by length() and you get constant complexity, that is O(1).
The length() method returns the number of characters present in the string. length vs length() 1. The length variable is applicable to an array but not for string objects whereas the length() method is applicable for string objects but not for arrays.
It is O(1) as the length is already known to String instance.
From JDK 1.6 it is visible.
public int length() {
return count;
}
Update
It is important to understand why they can cache the value of count and keep using same value for count. The reason lies in a great decision they took when designing String, its Immutability.
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