dp unique paths - find max profit - find best path with DFS

Author: lukeist

leetcode-62-UniquePaths.js

@@ -74,13 +74,19 @@ const uniquePaths = function (m, n, red) {
   console.log(arr);
 
   //   console.log(arr[m - 1][n - 1]);
-  return arr[m - 1][n - 1];
+  //   return arr[m - 1][n - 1];
 };
 
-uniquePaths(7, 3, [
+// uniquePaths(7, 3, [
+//   [1, 2],
+//   [5, 1],
+//   [3, 0],
+// ]);
+
+uniquePaths(3, 4, [
+  [1, 1],
   [1, 2],
-  [5, 1],
-  [3, 0],
+  [1, 3],
 ]);
 
 // // WITHOUT RED SQUARE

w-dp-uniquePaths-MaxProfit-leetcode62.js

@@ -0,0 +1,138 @@
+// 1. objective func: f(n) return max profit
+// 2. base cases:
+// f([1,1]) = 1
+// f([2,2]) = 2
+// 3. recurrent func:
+// f(y,x) = f[y][x] + Math.max(f(y-1,x) + f(x-1,y))
+
+// 4. order:
+// bottom up
+// 5. result: f(y-1,x-1)
+
+[
+  [0, 2, 4, 5],
+  [3, 4, 5, 6],
+  [7, 11, 13, 13],
+];
+////////////////////////////////////// FIND MAX PROFIT
+const traceMaxProfit = (grid) => {
+  // get max profit
+  for (y = 0; y < grid.length; y++) {
+    for (x = 0; x < grid[y].length; x++) {
+      grid[y][x] === "S" && (grid[y][x] = 0);
+      grid[y][x] === "E" && (grid[y][x] = 0);
+
+      if (grid[y - 1] === undefined && grid[y][x - 1] === undefined) {
+        continue;
+      } else if (grid[y - 1] === undefined) {
+        grid[y][x] += grid[y][x - 1];
+      } else if (grid[y][x - 1] === undefined) {
+        grid[y][x] += grid[y - 1][x];
+      } else {
+        grid[y][x] += Math.max(grid[y - 1][x], grid[y][x - 1]);
+      }
+    }
+  }
+
+  // trace back to find path
+
+  const stack = [[grid.length - 1, grid[0].length - 1]];
+
+  while (stack.length > 0) {
+    console.log(stack);
+
+    let [y, x] = stack.pop();
+
+    if (y === 0 && x === 0) {
+      grid[y][x] = "x";
+      break;
+    }
+
+    if (y === 0) {
+      grid[y][x] = "x";
+      stack.push([y, x - 1]);
+      continue;
+    }
+
+    if (x === 0) {
+      grid[y][x] = "x";
+      stack.push([y - 1, x]);
+      continue;
+    }
+
+    if (y > 0 && x > 0) {
+      grid[y - 1][x] > grid[y][x - 1] &&
+        (grid[y - 1][x] = "x") &&
+        stack.push([y - 1, x]);
+      grid[y - 1][x] < grid[y][x - 1] &&
+        (grid[y][x - 1] = "x") &&
+        stack.push([y, x - 1]);
+      continue;
+    }
+  }
+
+  console.log(stack);
+  console.log(grid);
+  //   for (y = grid.length - 1; y >= 0; y--) {
+  //     for (x = grid[y].length - 1; x >= 0; x--) {
+  //       if (y === 0 && x === 0) {
+  //         grid[y][x] = "x";
+  //       } else if (y === 0) {
+  //         // grid[y][x] = "x";
+  //         // continue;
+  //       } else if (x === 0) {
+  //         // grid[y][x] = "x";
+  //         // continue;
+  //       } else {
+  //         grid[y - 1][x] > grid[y][x - 1] && (grid[y - 1][x] = "x");
+  //         grid[y - 1][x] < grid[y][x - 1] && (grid[y][x - 1] = "x");
+  //       }
+  //     }
+  //   }
+
+  console.log(grid);
+  return grid;
+};
+
+// const gridT = [
+//   ["S", 2, 2, 1],
+//   [3, 1, 1, 1],
+//   [4, 4, 2, "E"],
+// ];
+const gridT = [
+  ["S", 2, 2, 1],
+  [3, 1, 1, 1],
+  [4, 4, 2, "E"],
+];
+
+traceMaxProfit(gridT);
+//
+// ////////////////////////////////////// FIND MAX PROFIT
+// const maxProfit = (grid) => {
+//   for (y = 0; y < grid.length; y++) {
+//     for (x = 0; x < grid[y].length; x++) {
+//       grid[y][x] === "S" && (grid[y][x] = 0);
+//       grid[y][x] === "E" && (grid[y][x] = 0);
+
+//       if (grid[y - 1] === undefined && grid[y][x - 1] === undefined) {
+//         continue;
+//       } else if (grid[y - 1] === undefined) {
+//         grid[y][x] += grid[y][x - 1];
+//       } else if (grid[y][x - 1] === undefined) {
+//         grid[y][x] += grid[y - 1][x];
+//         console.log("222");
+//       } else {
+//         grid[y][x] += Math.max(grid[y - 1][x], grid[y][x - 1]);
+//       }
+//     }
+//   }
+//   console.log(grid[y - 1][x - 1]);
+//   return grid[y - 1][x - 1];
+// };
+
+// const grid = [
+//   ["S", 2, 2, 1],
+//   [3, 1, 1, 1],
+//   [4, 4, 2, "E"],
+// ];
+// maxProfit(grid);