packagemedium;

publicclassSparseMatrixMultiplication {

publicint[][]multiply(int[][]A,int[][]B) {

intm =A.length,n =A[0].length,p =B[0].length;

int[][]C =newint[m][p];

for(inti =0;i <m;i++){

for(intj =0;j <n;j++){

if(A[i][j] !=0){

for(intk =0;k <p;k++){

if(B[j][k] !=0)C[i][k] +=A[i][j]*B[j][k];

}

}

}

}

returnC;

}

}

|338|[Counting Bits](https://leetcode.com/problems/counting-bits/)|[Solution](../../blob/master/MEDIUM/src/medium/CountingBits.java)| O(n)|O(n)| Medium|

|325|[Maximum Size Subarray Sum Equals k](https://leetcode.com/problems/maximum-size-subarray-sum-equals-k/)|[Solution] | O(n)|O(n) | Medium| HashMap

|314|[Binary Tree Vertical Order Traversal](https://leetcode.com/problems/binary-tree-vertical-order-traversal/)|[Solution](../../blob/master/MEDIUM/src/medium/BinaryTreeVerticalOrderTraversal.java)| O(n)|O(n) | Medium| HashMap, BFS

|311|[Sparse Matrix Multiplication](https://leetcode.com/problems/sparse-matrix-multiplication/)|[Solution](../../blob/master/MEDIUM/src/medium/SparseMatrixMultiplication.java)| O(m*n*l)|O(m*l)| Medium|

|301|[Remove Invalid Parentheses](https://leetcode.com/problems/remove-invalid-parentheses/)|[Solution]| ? | ? | Hard| BFS

|299|[Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/)|[Solution](../../blob/master/EASY/src/easy/BullsandCows.java)| O(n)|O(1)| Easy|

|295|[Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/)|[Solution](../../blob/master/HARD/src/hard/FindMedianFromDataStream.java)| O(nlogn) | O(n) | Hard| Heap