九章算法强化班ladder题目梳理.pdfVIP

九章算法强化班ladder题⽬梳理

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kth-smallest-number-in-sorted-matrix

Findthekthsmallestnumberinatrowandcolumnsortedmatrix.

[

[1,5,7],

[3,7,8],

[4,8,9],

]

注意点：

ComparatorPair的实现

PriorityQueuepolladd

1importjava.util.*;

2

3classPair{

4publicintx,y,val;

5publicPair(intx,inty,intval){

6this.x=x;

7this.y=y;

8this.val=val;

9}

10}

11

12classPairComparatorimplementsComparatorPair{

13publicintcompare(Paira,Pairb){

14returna.val-b.val;

15}

16}

17

18publicclassSolution{

19/**

20@param*matrix:amatrixofintegers

21@param*k:aninteger

22@return*:thekthsmallestnumberinthematrix

23*/

24publicintkthSmallest(int[][]matrix,intk){

25//writeyourcodehere

26int[]dx={0,1};

27int[]dy={1,0};

28intm=matrix.length;

29intn=matrix[0].length;

30boolean[][]visited=newboolean[m][n];

31PriorityQueuePairpq=newPriorityQueue(k,newPairComparator());

32pq.add(newPair(0,0,matrix[0][0]));

33

34for(inti=0;ik-1;i++){

35Paircur=pq.poll();

36for(intj=0;j2;j++){

37intx=cur.x+dx[j];

38inty=cur.y+dy[j];

39if(xmyn!visited[x][y]){

40pq.add(newPair(x,y,matrix[x][y]));

41visited[x][y]=true;

42

43}

44}

45}

46returnpq.peek().val;

47}

48}

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minimum-size-subarray-sum

Givenanarrayofnpositiveintegersandapositiveintegers,findtheminimallengthofasubarrayofwhichthesum≥s.Ifthereisnto