leetcode-go/written-exam/tencent-2017-summer/shift-upper.go

package main

import (
	"fmt"
)

func main() {
	var str []rune
	var s string
	_, err := fmt.Scanln(&s)
	for err == nil {
		str = []rune(s)
		for i, j := len(str)-1, len(str)-1; 1 <= i && 0 <= j; i-- {
			if isLower(str[i]) {
				for j = i - 1; 0 <= j && isLower(str[j]); j-- {
				}
				if j == -1 {
					break
				}
				for k := j + 1; k <= i; k++ {
					str[k-1], str[k] = str[k], str[k-1]
				}
				j--
			}
		}
		fmt.Println(string(str))
		_, err = fmt.Scanln(&s)
	}
}

func isLower(b rune) bool {
	return 'a' <= b && b <= 'z'
}