Row legalization

Row legalization. Global placement dropped the cells wherever wirelength was lowest, so they overlap and sit off the standard-cell rows. Legalize them: drag each cell onto a row (it snaps to the nearest one) and slide it sideways so no two cells overlap - while moving each as little as possible from its global-placement spot (the dashed ghost).

• On a row, no overlap - every cell on a row line, none overlapping.
• Displacement in budget - the total distance moved from the ghosts must stay under budget, so nudge, do not relocate. Legalization should barely disturb the placement.

Legalize with the least movement, then Submit design.