add new solutions

solutions/35/q3548/solution.go

@@ -0,0 +1,78 @@
+// Package q3548 implements a solution for https://leetcode.com/problems/equal-sum-grid-partition-ii/
+package q3548
+
+func findNumber(
+	num int,
+	r1, c1, r2, c2 int,
+	byVal map[int][][2]int32,
+	grid [][]int,
+) bool {
+	w, h := c2-c1+1, r2-r1+1
+	if w == 1 || h == 1 {
+		return grid[r1][c1] == num || grid[r2][c2] == num
+	}
+	for _, coord := range byVal[num] {
+		r, c := int(coord[0]), int(coord[1])
+		if r >= r1 && r <= r2 && c >= c1 && c <= c2 {
+			return true
+		}
+	}
+	return false
+}
+
+func canPartitionGrid(grid [][]int) bool {
+	w, h := len(grid[0]), len(grid)
+	hSums, vSums := make([]int, w), make([]int, h)
+	sumAll := 0
+	byVal := make(map[int][][2]int32, w*h)
+
+	for r := range h {
+		for c := range w {
+			val := grid[r][c]
+			hSums[c] += val
+			vSums[r] += val
+			sumAll += val
+			byVal[val] = append(byVal[val], [2]int32{int32(r), int32(c)})
+		}
+	}
+
+	// Check vertical cuts
+	sum := 0
+	for i := range w - 1 {
+		sum += hSums[i]
+		rem := sumAll - sum
+		if sum > rem {
+			if findNumber(sum-rem, 0, 0, h-1, i, byVal, grid) {
+				return true
+			}
+		} else if sum < rem {
+			if findNumber(rem-sum, 0, i+1, h-1, w-1, byVal, grid) {
+				return true
+			}
+		} else {
+			return true
+		}
+	}
+
+	// Check horizontal cuts
+	sum = 0
+	for i := range h - 1 {
+		sum += vSums[i]
+		rem := sumAll - sum
+		if sum > rem {
+			if findNumber(sum-rem, 0, 0, i, w-1, byVal, grid) {
+				return true
+			}
+		} else if sum < rem {
+			if findNumber(rem-sum, i+1, 0, h-1, w-1, byVal, grid) {
+				return true
+			}
+		} else {
+			return true
+		}
+	}
+
+	return false
+}
+
+var _ = canPartitionGrid