**Problem Description** :

Given a data stream input of non-negative integers a1, A2, ..., summarize the numbers seen so far as a list of Di Sjoint intervals.

**Problem Solving Ideas:**

This problem is the latest problem, in fact, the idea is easy to find, the difficulty is to take into account all possible circumstances.

The first thing to determine is that the class must have a collection class List<interval> that holds the current result, and that its elements are sorted by the size of the starting value of the Interval, when the call to Getintervals () is returned directly to the lists when the Addnum (Val) Class is adjusted for classes in list<interval>. The specific adjustment steps are as follows:

1) Call the custom findindex (int val) method to find the value of the interval starting value that is less than the maximum interval of Val. The specific lookup process can be found using binary methods. Two special cases need to be considered: the Val value is smaller than the starting value of the interval with position 0, or greater than the starting value of the last interval. These two cases can be handled with special treatment (return 1, and lists.size () 1) respectively.

2) Consider the following for the return value (just give specific examples, I believe you can understand):

If the return value is-1:

A. If the current value is 1 and the interval value of position 0 is (2,x), this interval can be modified (1,x);

B. If the current value is 1 and the interval value at position 0 is (3,x), you can create a new interval () and join lists.

If the return value is Lists.size ()-1:

A. If the current value is 11, the last interval is (8,11), do not modify;

B. If the current value is 11, the last Intever is (8,10), it needs to be changed to (8,11);

C. If the current value is 11 and the last Intever is (8,9), you need to create a new (11,11) and join lists.

If the return value of POS is in [0,lists.size ()-1);

A. If Val==lists.get (pos+1). Start-1 && Val==lists.get (POS). End+1: Two interval need to be merged into a new interval;

B. If Val==lists.get (pos+1). Start-1 && val! =lists.get (POS). End+1: Need to modify the value of lists[pos+1];

C. If Val==lists.get (pos+1). Start-1 && Val==lists.get (POS). end+1 need to modify the value of Lists[pos];

D. Other situation: Create a new interval: (Val,val) and add to lists.

**Specific code:**

1 Public classSummaryranges {2 3List<interval>lists;4 /**Initialize your data structure here.*/5 Publicsummaryranges () {6lists=NewArraylist<interval>();7 8 }9 Ten Public voidAddnum (intval) { One if(Lists.size () ==0){ AInterval p =NewInterval (val,val); - Lists.add (p); - return; the } - if(Lists.size () ==1){ - if(Lists.get (0). End <val) { -Interval P=lists.remove (0); + if(P.END==VAL-1){ -Interval p1=NewInterval (p.start,val); + Lists.add (p1); A return; at } -Interval p1=NewInterval (val,val); - Lists.add (p); - Lists.add (p1); - - return; in } - Else if(Lists.get (0). Start >val) { toInterval P=lists.remove (0); + if(p.start==val+1){ -Interval p1=NewInterval (val,p.start); the Lists.add (p1); * $ return;Panax Notoginseng } -Interval p1=NewInterval (val,val); the Lists.add (p1); + Lists.add (p); A the return; + } - Else{ $ return; $ } - } - intpos=FindIndex (val); the if(Pos==-1){ - if(Val==lists.get (0). start-1){WuyiLists.get (0). start=Val; the return; - } Wu Else{ -Interval p1=NewInterval (val,val); AboutLists.add (0, p1); $ return; - } - } - if(Pos==lists.size ()-1){ A if(val<=Lists.get (POS). End) { + return; the } - Else{ $ if(Val==lists.get (POS). end+1){ theLists.get (POS). end=Val; the return; the } the Else{ -Interval p1=NewInterval (val,val); in Lists.add (p1); the the return; About } the } the } the + if(val<=Lists.get (POS). End) { - return; the }Bayi Else if(Val==lists.get (pos+1). Start-1 && Val==lists.get (POS). end+1){ theInterval p1=Lists.remove (POS); theInterval p2=Lists.remove (POS); -Interval p=NewInterval (P1.start, p2.end); - the Lists.add (POS, p); the return; the } the Else if(Val==lists.get (pos+1). start-1){ -Lists.get (pos+1). start=Val; the return; the } the Else if(Val==lists.get (POS). end+1){94Lists.get (POS). end=Val; the return; the } the Else{98Interval p=NewInterval (Val, Val); AboutLists.add (pos+1, p); - 101 return;102 }103 104 } the 106 PublicList<interval>getintervals () {107 returnlists;108 }109 the Private intFindIndex (intval) {111 intStart=0; the intEnd=lists.size ()-1;113 if(Lists.get (0) .start>val) the return-1; the if(Lists.get (Lists.size ()-1) .start<val) the returnLists.size ()-1;117 while(start<end) {118 intMid= (start+end)/2;119 if(val<Lists.get (mid). Start) { -End=mid-1;121 }122 Else if(val>Lists.get (mid). Start) {123 if(Val<lists.get (mid+1). Start)124 returnmid; the Else126Start= mid+1;127 } - Else129 returnmid; the }131 returnstart; the }133}

The steps may be cumbersome and will continue to optimize the code later.

352. Data Stream as disjoint intervals