add: leetcode 1034 solution

leetcode/1034.Coloring-A-Border/1034.Coloring A Border.go

@@ -0,0 +1,53 @@
+package leetcode
+
+type point struct {
+	x int
+	y int
+}
+
+var (
+	borders       []point
+	m             int
+	n             int
+	vis           [][]bool
+	dirs          []point
+	q             []point
+	originalColor int
+)
+
+func colorBorder(grid [][]int, row, col, color int) [][]int {
+	m, n = len(grid), len(grid[0])
+	vis = make([][]bool, m)
+	for i := range vis {
+		vis[i] = make([]bool, n)
+	}
+	dirs = []point{{1, 0}, {-1, 0}, {0, 1}, {0, -1}}
+	originalColor = grid[row][col]
+	borders = []point{}
+	q = []point{{row, col}}
+	bfs(q, grid)
+	for _, p := range borders {
+		grid[p.x][p.y] = color
+	}
+	return grid
+}
+
+func bfs(q []point, grid [][]int) {
+	for len(q) != 0 {
+		ele := q[0]
+		vis[ele.x][ele.y] = true
+		q = q[1:]
+		isBorder := false
+		for _, dir := range dirs {
+			nx, ny := ele.x+dir.x, ele.y+dir.y
+			if !(0 <= nx && nx < m && 0 <= ny && ny < n && grid[nx][ny] == originalColor) {
+				isBorder = true
+			} else if !vis[nx][ny] {
+				q = append(q, point{nx, ny})
+			}
+		}
+		if isBorder {
+			borders = append(borders, point{ele.x, ele.y})
+		}
+	}
+}