Create 1074. Number of Submatrices That Sum to Target

Author: rajatag03

Diff for: 1074. Number of Submatrices That Sum to Target

@@ -0,0 +1,31 @@
+class Solution {
+    public int numSubmatrixSumTarget(int[][] matrix, int target) {
+        int m = matrix.length,n=matrix[0].length;
+        
+        for(int row =0;row<m;row++){
+            for(int col=1;col<n;col++){
+                matrix[row][col]+=matrix[row][col-1];
+            }
+        }
+        
+        int count=0;
+        
+        for(int c1=0;c1<n;c1++){
+            for(int c2=c1;c2<n;c2++){
+                
+                Map<Integer,Integer> map = new HashMap<>();
+                map.put(0,1);
+                int sum=0;
+                
+                for(int row=0;row<m;row++){
+                    sum += matrix[row][c2] - (c1>0 ? matrix[row][c1-1] : 0);
+                    count += map.getOrDefault(sum-target,0);
+                    map.put(sum,map.getOrDefault(sum,0)+1);
+                }
+                
+            }
+        }
+        
+        return count;
+    }
+}