DSA : Day 1

Happy Learning! Happy Programming!

Topics

1?? Decimal to Binary, Binary to Decimal

??Binary of -ve numbers ? Sign Magnitude vs 2s Complement

2?? Data Types

??Primitive Data Types

??Data Types: Space and Range [VVI for solving problems (reflect CONSTRAINTS)]

??Signed vs Unsigned

3?? Errors

??Compile Time Error

??Runtime Error

??Time Limit Exceeded Error

??Wrong Answer

4?? Operators

??Arithmetic: +, -, *, /, %

??Logical: &&, ||, !

??Relational: <, >, <=, >=, ==, !=

??Bitwise: amp;, |, ^, ~, <<, >>

??Assignment: =, +=, -=, ...

??Unary: +, -, ++, --

??Miscellaneous Operators: ???: : Ternary (conditional) operator??, : Comma operator??: Size of an object??. : Member access operator (dot)??->; : Member access operator (arrow)??[] : Array subscript??() : Function call

Data Types

??Primitive Data Type

??Sizes & Constraint Ranges

• int --> 4 B --> (2*10^9)
• long --> 4/8 B long long --> 8 B --> (9*10^18)
• float --> 4 B
• double --> 8 B

??Key Points

• 'string' is not a primitive data type
• Data type 'byte' exists only in Java
• Keywords 'unsigned' and 'long long' in Java, unlike C++.
• 'long long' in C++ = 'long' in Java.
• 'long' in C++ can be of 4 or 8 bytes, based on the system architecture. But, takes 8 bytes in Java.
• By default, all primitive datatypes are 'signed'.
• Range of signed = (-2^n-1 to 2^n-1 - 1)
• Range of unsigned = (0 to 2^n - 1) ; where n = #bits
• 'double' provides more precision than 'float'. Good Practice: Always use double instead of float incase of decimals.

Errors

??Compile Time Error (CTE): Example: Type mismatches, unresolved references.

??Runtime Error (RTE):Example: Division by zero, accessing out-of-bounds array elements.

??Time Limit Exceeded Error (TLE): If there exists some better solution with lesser time complexity.

??Wrong Answer

??Syntax Error: Example: Missing semicolons, unmatched brackets.