From 6e0cdece4770a465ede52530adfebcacce23ec69 Mon Sep 17 00:00:00 2001
From: Grzegorz Kucmierz <gkucmierz@gmail.com>
Date: Tue, 17 Dec 2019 16:35:16 +0100
Subject: [PATCH] Minimum path in squares

---
 minimum-path-in-squares/index.js | 52 ++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 minimum-path-in-squares/index.js

diff --git a/minimum-path-in-squares/index.js b/minimum-path-in-squares/index.js
new file mode 100644
index 0000000..e56b8b4
--- /dev/null
+++ b/minimum-path-in-squares/index.js
@@ -0,0 +1,52 @@
+// https://www.codewars.com/kata/minimum-path-in-squares/javascript
+
+// this solution taht works is not actually minimum path
+function minPath(grid, x, y) {
+  const [X, Y] = [0, 1];
+  const row = new Array(x+1).fill(0);
+  for (let i = 0; i <= y; ++i) {
+    row[0] += grid[i][0];
+    for (let j = 1; j <= x; ++j) {
+      if (i === 0) {
+        
+      }
+      if (i === 0) {
+        row[j] = row[j-1] + grid[i][j];  
+      } else {
+        row[j] = Math.min(row[j-1], row[j]) + grid[i][j];
+      }
+    }
+  }
+  return row.pop();
+}
+
+// this solution calculates minimum path
+function minPath2(grid, x, y) {
+  const [X, Y] = [0, 1];
+  const [w, h] = [grid[0].length, grid.length];
+  const m = new Array(h).fill(0).map(_ => new Array(w).fill(Infinity));
+  
+  const check = [
+    [0, 0, 0] // x, y, sum
+  ];
+  
+  const path = (grid, m, x, y, sum) => {
+    if (x < 0 || y < 0) return;
+    if (w <= x || h <= y) return;
+    const newSum = sum + grid[y][x];
+    if (newSum < m[y][x]) {
+      m[y][x] = newSum;
+      [[-1, 0], [1, 0], [0, -1], [0, 1]].map(diff => {
+        check.push([x+diff[X], y+diff[Y], newSum]);
+      });
+    }
+  };
+  
+  let cnt = 0;
+  while (check.length) {
+    ++cnt;
+    const ch = check.shift();
+    path(grid, m, ...ch);
+  }
+  return m[y][x];
+}