# Simple java using List Beats 98.42%

• List is easy to record snake's body by shifting to right
If eating food in this move, just add new position at end of List;
else, remove the first element and check whether the new head in list.

``````class SnakeGame {
int[][] food;
List<Integer> snakeBody;
int m, n;
int f;
/** Initialize your data structure here.
@param width - screen width
@param height - screen height
@param food - A list of food positions
E.g food = [[1,1], [1,0]] means the first food is positioned at [1,1], the second is at [1,0]. */
public SnakeGame(int width, int height, int[][] food) {
m = height;
n = width;
f = 0;
snakeBody = new ArrayList<>();
snakeBody.add(0);
this.food = food;
}

/** Moves the snake.
@param direction - 'U' = Up, 'L' = Left, 'R' = Right, 'D' = Down
@return The game's score after the move. Return -1 if game over.
Game over when snake crosses the screen boundary or bites its body. */
public int move(String direction) {
int dx = 0, dy = 0;
switch (direction) {
case "U" : dx = -1; dy = 0;
break;
case "L" : dx = 0; dy = -1;
break;
case "R" : dx = 0; dy = 1;
break;
case "D" : dx = 1; dy = 0;
break;
}
int index = snakeBody.get(snakeBody.size() - 1);
int nx = index / n + dx;
int ny = index % n + dy;
if (nx < 0 || nx >= m || ny < 0 || ny >= n) return -1;
if (f < food.length && nx == food[f][0] && ny == food[f][1]) {
f++;
snakeBody.add(nx * n + ny);
return f;
} else {
snakeBody.remove(0);
if (snakeBody.contains(nx * n + ny)) {
return -1;
}
snakeBody.add(nx * n + ny);
return f;
}
}
}
``````

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