Commit0e5ae7d

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restore

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Original file line number	Diff line number	Diff line change
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	`1`	`+packageAlgorithms.string;`
	`2`	`+`
	`3`	`+importjava.util.ArrayList;`
	`4`	`+importjava.util.List;`
	`5`	`+`
	`6`	`+publicclassRestoreIpAddresses {`
	`7`	`+publicList<String>restoreIpAddresses(Strings) {`
	`8`	`+if (s ==null) {`
	`9`	`+returnnull;`
	`10`	`+ }`
	`11`	`+`
	`12`	`+ArrayList<String>ret =newArrayList<String>();`
	`13`	`+ArrayList<String>path =newArrayList<String>();`
	`14`	`+`
	`15`	`+dfs(s,0,path,ret);`
	`16`	`+`
	`17`	`+returnret;`
	`18`	`+ }`
	`19`	`+`
	`20`	`+publicvoiddfs(Strings,intindex,ArrayList<String>path,ArrayList<String>ret) {`
	`21`	`+if (path.size() ==4) {`
	`22`	`+if (index ==s.length() &&path.size() ==4) {`
	`23`	`+StringBuildersb =newStringBuilder();`
	`24`	`+for (Stringstr:path) {`
	`25`	`+sb.append(str);`
	`26`	`+sb.append('.');`
	`27`	`+ }`
	`28`	`+`
	`29`	`+sb.deleteCharAt(sb.length() -1);`
	`30`	`+ret.add(sb.toString());`
	`31`	`+ }`
	`32`	`+`
	`33`	`+return;`
	`34`	`+ }`
	`35`	`+`
	`36`	`+intlen =s.length();`
	`37`	`+for (inti =index;i <index +3 &&i <len;i++) {`
	`38`	`+if (s.charAt(index) =='0' &&i >index) {`
	`39`	`+break;`
	`40`	`+ }`
	`41`	`+`
	`42`	`+Stringpre =s.substring(index,i +1);`
	`43`	`+// 过滤Number > 255的情况。`
	`44`	`+intnum =Integer.parseInt(pre);`
	`45`	`+if (num >255) {`
	`46`	`+continue;`
	`47`	`+ }`
	`48`	`+`
	`49`	`+path.add(pre);`
	`50`	`+dfs(s,i +1,path,ret);`
	`51`	`+path.remove(path.size() -1);`
	`52`	`+ }`
	`53`	`+ }`
	`54`	`+}`

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