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;

}

}