Snap_Diff
题意大概是实现linux里面的diff的功能,给你两个文件,如果f1比f2多的,就打印“-someContent”, 如果是f2比f1多的,就打印“+someContent”
思路大概就是
对f2简历一个map,来记录每个line的
对于f1里面每一个line
如果map里面不包含这个line
打印"-line"
否则
把这条记录的计数减一
如果减完是0
就删除
如果map还有剩的,就打印出来“+line”
代码:
public void printDiff(List<String> f1, List<String> f2) {
Map<String, Integer> counter = new HashMap<>();
for(String line: f2) {
if(counter.containsKey(line)) {
counter.put(line, counter.get(line) + 1);
} else {
counter.put(line, 1);
}
}
for(String line: f1) {
if(!counter.containsKey(line)) {
System.out.println("-" + line);
} else {
if(counter.get(line) == 0) {
counter.remove(line);
} else {
counter.put(line, counter.get(line) - 1);
}
}
}
for(Map.Entry<String, Integer> entry: counter.entrySet()) {
for(int i = 0; i < entry.getValue(); i++) {
System.out.println("+" + entry.getKey());
}
}
}
public static void main(String[] args) {
SnapDiff sample = new SnapDiff();
List<String> f1 = new ArrayList<>(Arrays.asList("A", "B", "C", "D", "E"));
List<String> f2 = new ArrayList<>(Arrays.asList("A", "B", "D"));
sample.printDiff(f1, f2);
}