翻转字符串

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/** * Created by lxw, liwei4939@126.com on 2017/10/31. * 翻转字符串 */public class reverseString {    public void rotateWord(char[] chas){        if(chas == null || chas.length == 0){            return;        }        reverse(chas, 0, chas.length - 1);        int l = -1;        int r =-1;        for (int i =0; i < chas.length; i++){            if(chas[i] != ' '){                l = i == 0 ||chas[i-1] == ' ' ? i : l;                r = i == chas.length -1 || chas[i+1] == ' ' ? i : r;            }            if(l != ' ' && r != ' '){                reverse(chas, l, r);                l = -1;                r = -1;            }        }    }    public void reverse(char[] chas, int start, int end){        char tmp = 0;        while (start < end){            tmp = chas[start];            chas[start] = chas[end];            chas[end] = tmp;            start++;            end--;        }    }    public void rotate1(char[] chas, int size){        if(chas == null || size <= 0 || size >= chas.length){            return;        }        reverse(chas, 0, size - 1);        reverse(chas, size, chas.length - 1);        reverse(chas, 0, chas.length -1);    }    public void rotate2(char[] chas, int size){        if(chas == null || size <= 0 || size >= chas.length){            return;        }        int start = 0;        int end = chas.length - 1;        int lpart = size;        int rpart = chas.length - size;        int s = Math.min(lpart, rpart);        int d = lpart - rpart;        while (true){            exchange(chas, start, end, s);            if(d == 0){                break;            } else if(d > 0){                start += s;                lpart = d;            } else {                end -= s;                rpart = -d;            }            s = Math.min(lpart, rpart);            d = lpart - rpart;        }    }    public void exchange(char[] chas, int start, int end, int size){        int i = end - size + 1;        char tmp = 0;        while (size-- != 0){            tmp = chas[start];            chas[start] = chas[i];            chas[i] = tmp;            start++;            i++;        }    }    public static void main(String[] args){        reverseString obj = new reverseString();        String str = "1234567ABCD";        char[] arrStr = str.toCharArray();        int size = 7;        obj.rotate2(arrStr, size);        System.out.println(arrStr);    }}
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