No, putting a bucket of water in a room with an air conditioner will not effectively humidify the air in that room. Air conditioners are designed to cool the air by removing heat and moisture from it. When warm air passes through the cooling coils of an air conditioner, the moisture in the air condenses and is typically collected and drained away. This process reduces the humidity of the air.
Adding a bucket of water to the room will not counteract the dehumidifying effect of the air conditioner. While some water may evaporate from the bucket, the amount of moisture added to the air will be minimal compared to the dehumidifying effect of the air conditioner.
If you want to increase the humidity in a room, there are more effective methods to consider. You could use a humidifier specifically designed for adding moisture to the air or place bowls of water near a heat source to promote evaporation. These methods are more efficient at increasing the humidity levels in a controlled manner.