Leetcode 1326. Minimum Number of Taps to Open to Water a Garden

Given n and ranges for taps at positions 0..n (each tap i covers [i - ranges[i], i + ranges[i]]), find the minimum number of taps whose intervals together cover the entire segment [0, n], or return -1 if impossible. This is an interval-cover/jump-game style problem solvable by greedily selecting the interval with the farthest right reach at each step.