From b3f3754634202af94cc7f345ee19d76ddbe55d65 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Fri, 26 Apr 2024 19:55:26 +0200
Subject: [PATCH] =?UTF-8?q?cs:=20add=20=C2=AB1289.=20Minimum=20Falling=20P?=
 =?UTF-8?q?ath=20Sum=20II=C2=BB?=
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Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 cs/minimum-falling-path-sum-ii.cs | 44 +++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 cs/minimum-falling-path-sum-ii.cs

diff --git a/cs/minimum-falling-path-sum-ii.cs b/cs/minimum-falling-path-sum-ii.cs
new file mode 100644
index 0000000..7389dcf
--- /dev/null
+++ b/cs/minimum-falling-path-sum-ii.cs
@@ -0,0 +1,44 @@
+public class Solution {
+    private int[,] PrepareDP(int[][] grid) {
+        int[,] dp = new int[grid.Length, grid.Length];
+
+        var y = grid.Length - 1;
+        for (var x = 0; x < grid.Length; ++x) {
+            dp[y, x] = grid[y][x];
+        }
+
+        return dp;
+    }
+
+    private void Compute(int[][] grid, int[,] dp, int y, int x0) {
+        var minimum = int.MaxValue;
+
+        for (var x = 0; x < grid.Length; ++x) {
+            // need to continue with different column
+            if (x == x0) {
+                continue;
+            }
+
+            minimum = Math.Min(minimum, dp[y + 1, x]);
+        }
+
+        dp[y, x0] = grid[y][x0] + minimum;
+    }
+
+    public int MinFallingPathSum(int[][] grid) {
+        var dp = PrepareDP(grid);
+
+        for (var y = grid.Length - 2; y >= 0; --y) {
+            for (var x = 0; x < grid.Length; ++x) {
+                Compute(grid, dp, y, x);
+            }
+        }
+
+        int minFallingPath = int.MaxValue;
+        for (var x = 0; x < grid.Length; ++x) {
+            minFallingPath = Math.Min(minFallingPath, dp[0, x]);
+        }
+
+        return minFallingPath;
+    }
+}