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