unique paths

Author: se6816

unique-paths/se6816.java

@@ -0,0 +1,48 @@
+class Solution {
+    public int[] moveX = {0, 1};
+    public int[] moveY = {1, 0};
+    int N;
+    int M;
+    public int uniquePaths(int m, int n) {
+        int[][] dp = new int[m][n];
+        boolean[][] visited = new boolean[m][n];
+        int curX = 0;
+        int curY = 0;
+        N = n;
+        M = m;
+        dp[curX][curY] = 1;
+        visited[curX][curY] = true;
+        Queue<int[]> que = new ArrayDeque<>();
+        que.offer(new int[]{0,0});
+
+        while(!que.isEmpty()) {
+            int[] data = que.poll();
+
+            for(int i = 0; i < 2; i++) {
+                int tempX = data[0] + moveX[i];
+                int tempY = data[1] + moveY[i];
+
+                if(isOutOfIndex(tempX, tempY)) {
+                    continue;
+                }
+
+                dp[tempX][tempY] += dp[data[0]][data[1]];
+
+
+                if(visited[tempX][tempY]) {
+                    continue;
+                }
+                visited[tempX][tempY] = true;
+                que.add(new int[]{tempX, tempY});
+
+            }
+        }
+
+        return dp[M-1][N-1];
+
+    }
+
+    public boolean isOutOfIndex(int x, int y) {
+        return x < 0 || x >= M || y < 0 || y >=N;
+    }
+}