2906. Construct Product Matrix

2026-03-25 11:50:01 +03:00
parent 1e973f5a9e
commit a3131bf6d0
2 changed files with 154 additions and 2 deletions
--- a/Matrix/Solution.cs
+++ b/Matrix/Solution.cs
@@ -0,0 +1,80 @@
+public class Solution
+{
+    struct MulInfo
+    {
+        public long Left;
+        public long Right;
+    }
+
+
+    public int[][] ConstructProductMatrix(int[][] grid)
+    {
+        var mod = 12345;
+        var table = new MulInfo[grid.Length][];
+
+        var lastRow = grid.Length - 1;
+        var lastCol = grid[0].Length - 1;
+
+        // прямой проход
+        for (var i = 0; i < grid.Length; i++)
+        {
+            table[i] = new MulInfo[grid[i].Length];
+            for (var j = 0; j < grid[i].Length; j++)
+            {
+                if (j == 0 && i == 0)
+                {
+                    table[i][j].Left = grid[i][j] % mod;
+                }
+                else if (j > 0)
+                {
+                    table[i][j].Left = table[i][j - 1].Left * grid[i][j] % mod;
+                }
+                else if (i > 0)
+                {
+                    table[i][j].Left = table[i - 1][lastCol].Left * grid[i][j];
+                    table[i][j].Left %= mod;
+                }
+
+            }
+        }
+
+        // обратный проход
+        for (var i = lastRow; i >= 0; i--)
+        {
+            for (var j = lastCol; j >= 0; j--)
+            {
+                if (j == lastCol && i == lastRow)
+                {
+                    table[i][j].Right = grid[i][j] % mod;
+                }
+                else if (j < lastCol)
+                {
+                    table[i][j].Right = table[i][j + 1].Right * grid[i][j] % mod;
+                }
+                else if (i < lastRow)
+                {
+                    table[i][j].Right = table[i + 1][0].Right * grid[i][j] % mod;
+                }
+                
+                var left = 1L;
+                var right = 1L;
+                if (i == 0 && j == 0)
+                    left = 1;
+                else if (j > 0)
+                    left = table[i][j - 1].Left;
+                else if (i > 0)
+                    left = table[i - 1][lastCol].Left;
+
+                if (i == lastRow && j == lastCol)
+                    right = 1;
+                else if (j < lastCol)
+                    right = table[i][j + 1].Right;
+                else if (i < lastRow)
+                    right = table[i + 1][0].Right;
+                grid[i][j] = (int)(left * right % mod);
+            }
+        }
+
+        return grid;
+    }
+}