Greedy Algorithms
Greedy algorithms construct a solution by making a sequence of locally optimal choices, hoping to arrive at a global optimum. Sorting the input is often a critical first step.
A common greedy strategy where sorting the input by a specific criterion simplifies the problem, allowing for a linear pass to make locally optimal choices.
Example Problems:
Merge IntervalsNon-overlapping IntervalsMinimum Number of Arrows to Burst Balloons
Solution Spotlight: Merge Intervals
The greedy strategy is to sort the intervals by their start times. This ensures that when considering an interval, all intervals that could potentially overlap with it and start earlier have already been processed and merged. This ordering allows us to make a simple, locally optimal decision: either merge with the last interval in our result or add a new one.
MergeIntervals.java
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