optimize memory layout

Prioritize memory-efficient data structures and algorithms by favoring stack allocation over heap allocation, utilizing bit packing for compact storage, and applying proper bit masking for data integrity. When designing iterators or containers, consider whether operations can avoid dynamic allocation - most backtracking scenarios use empty vectors that don’t require heap allocation. For packed data structures, use bit masking to ensure only valid bits are stored and prevent data corruption.

Example of proper bit masking:

// Instead of direct assignment
flags_.direction = static_cast<uint8_t>(direction);

// Use masking to ensure only valid bits
flags_.direction = static_cast<uint8_t>(direction) & 0x03;

For memory layout optimization, combine related fields to utilize alignment padding:

// Before: wastes alignment bits
bool flag1 : 1;
bool flag2 : 1; 
uint32_t generation = 0;  // 32 bits but alignment wastes space

// After: pack into available bits
bool flag1 : 1;
bool flag2 : 1;
uint8_t generation = 0;  // Fits in remaining alignment space

Always validate that algorithmic optimizations maintain correctness - performance improvements should not compromise the fundamental behavior of the algorithm.