sparse matrix multiplication

fishercoder1534 · fishercoder1534 · commit d4233aa63675 · 2016-11-24T10:15:05.000-08:00
diff --git a/MEDIUM/src/medium/SparseMatrixMultiplication.java b/MEDIUM/src/medium/SparseMatrixMultiplication.java
@@ -0,0 +1,20 @@
+package medium;
+
+public class SparseMatrixMultiplication {
+
+    public int[][] multiply(int[][] A, int[][] B) {
+        int m = A.length, n = A[0].length, p = B[0].length;
+        int[][] C = new int[m][p];
+        for(int i = 0; i < m; i++){
+            for(int j = 0; j < n; j++){
+                if(A[i][j] != 0){
+                    for(int k = 0; k < p; k++){
+                        if(B[j][k] != 0) C[i][k] += A[i][j]*B[j][k];
+                    }
+                }
+            }
+        }
+        return C;
+    }
+
+}
diff --git a/README.md b/README.md
@@ -41,6 +41,7 @@
 |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
