763 partition labels

763. 划分字母区间

go：

func partitionLabels(s string) []int {
    var last [26]int
    for i := 0; i < len(s); i++ {
        last[s[i] - 'a'] = i
    }

    res, start, end := make([]int, 0), 0, 0
    for i := 0; i < len(s); i++ {
        if last[s[i] - 'a'] > end {
            end = last[s[i] - 'a']
        }
        if i == end {
            res = append(res, end - start + 1)
            start = i + 1
        }
    }

    return res
}