Missing Ranges(Medium)

Given a sorted integer array where the range of elements are [0, 99] inclusive, return its missing ranges. For example, given [0, 1, 3, 50, 75], return [“2”, “4->49”, “51->74”, “76->99”]

[分析] 一遍线性扫描即可。

Java代码：

public List<String> findMissingRanges(int[] vals, int start, int end) {
    List<String> ranges = new ArrayList<String>();
    int prev = start - 1;
    for (int i=0; i<=vals.length; ++i) {
        int curr = (i==vals.length) ? end + 1 : vals[i];
        if ( cur-prev>=2 ) {
            ranges.add(getRange(prev+1, curr-1));
        }
        prev = curr;
    }
    return ranges;
}

private String getRange(int from, int to) {
    return (from==to) ? String.valueOf(from) : from + "->" + to;
}