<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<style type="text/css">
*body{margin:0 auto;}
status{
position: absolute;
left: 50%;
top: 170px;
margin-left: 60px;
}
.background {
background: rgb(52, 166, 251);
table-layout: fixed;
border-spacing: 0;
}
.background td { padding: 0; }
.lava { background: rgb(255, 100, 100); }
.wall { background: white; }
.actor { position: absolute; }
.coin { background: rgb(241, 229, 89); }
.player { background: rgb(64, 64, 64); }
.lost .player { background: rgb(160, 64, 64); }
.won .player {
box-shadow: -4px -7px 8px white, 4px -7px 8px white;
}
.game {
overflow: hidden;
max-width: 600px;
max-height: 450px;
position: relative;
}
</style>
</head>
<body>
<img style="position: absolute;right: 0;top: 0;" src=" http://a4.qpic.cn/psb?/V13id91S0o4nYt/y9R.1dX5WxfYfZzDqBMG2hsjLT7LiZjPoCPYg.6gxhk!/b/dEMBAAAAAAAA&ek=1&kp=1&pt=0&bo=LAGyAQAAAAARF74!&vuin=206105759&tm=1522486800&sce=60-2-2&rf=viewer_4">
<div id='status'>How many lives you have left: <span id="lives"></span></div>
<script type="text/javascript">
/*
Based on Dark Blue by Thomas Palef.
Plans are submitted as an array of strings that forms a grid.
@ = Player start position
o = Coins
x = Solid surfaces
! = Non-moving lava
= = Vertical moving lava
v = Dripping lava
| = Horizontal moving lava
*/
var simpleLevelPlan = [
" ",
" ",
" x = x ",
" x o o x ",
" x @ xxxxx x ",
" xxxxx x ",
" x!!!!!!!!!!!!x ",
" xxxxxxxxxxxxxx ",
" "
];
var GAME_LEVELS = [
[" ",
" ",
" ",
" ",
" ",
" ",
" xxx ",
" xx xx xx!xx ",
" o o xx x!!!x ",
" xx!xx ",
" xxxxx xvx ",
" xx ",
" xx o o x ",
" x o x ",
" x xxxxx o x ",
" x xxxx o x ",
" x @ x x xxxxx x ",
" xxxxxxxxxxxx xxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxxxxxx xxxxxxxxx ",
" x x x x ",
" x!!!x x!!!!!x ",
" x!!!x x!!!!!x ",
" xxxxx xxxxxxx ",
" ",
" "],
[" x!!x xxxxxxx x!x ",
" x!!x xxxx xxxx x!x ",
" x!!xxxxxxxxxx xx xx x!x ",
" xx!!!!!!!!!!xx xx xx x!x ",
" xxxxxxxxxx!!x x o o o x!x ",
" xx!x x o o xx!x ",
" x!x x xxxxxxxxxxxxxxx!!x ",
" xvx x x x !!!!!!!!!!!!!!xx ",
" xx | | | xx xxxxxxxxxxxxxxxxxxxxx ",
" xx!!!!!!!!!!!xx v ",
" xxxx!!!!!xxxx ",
" x x xxxxxxx xxx xxx ",
" x x x x x x ",
" x x x x ",
" x x xx x ",
" xx x x x ",
" x x o o x x x x ",
" xxxxxxx xxx xxx x x x x x x ",
" xx xx x x x x xxxxxx x x xxxxxxxxx x ",
" xx xx x o x x xx x x x x ",
" @ x x x x x x x x x x ",
" xxx x x x x x x x xxxxx xxxxxx x ",
" x x x x xx o xx x x x o x x x ",
"!!!!x x!!!!!!x x!!!!!!xx xx!!!!!!!!xx x!!!!!!!!!! x = x x x ",
"!!!!x x!!!!!!x x!!!!!xx xxxxxxxxxx x!!!!!!!xx! xxxxxxxxxxxxx xx o o xx ",
"!!!!x x!!!!!!x x!!!!!x o xx!!!!!!xx ! xx xx ",
"!!!!x x!!!!!!x x!!!!!x xx!!!!!!xx ! xxxxxxx ",
"!!!!x x!!!!!!x x!!!!!xx xxxxxxxxxxxxxx!!!!!!xx ! ",
"!!!!x x!!!!!!x x!!!!!!xxxxxxxxx!!!!!!!!!!!!!!!!!!xx ! ",
"!!!!x x!!!!!!x x!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!xx ! "],
[" ",
" ",
" ",
" ",
" ",
" o ",
" ",
" x ",
" x ",
" x ",
" x ",
" xxx ",
" x x !!! !!! xxx ",
" x x !x! !x! ",
" xxx xxx x x ",
" x x x oooo x xxx ",
" x x x x x!!!x ",
" x x xxxxxxxxxxxx xxx ",
" xx xx x x x ",
" x xxxxxxxxx xxxxxxxx x x ",
" x x x x!!!x ",
" x x x xxx ",
" xx xx x ",
" x x= = = = x xxx ",
" x x x x!!!x ",
" x x = = = =x o xxx xxx ",
" xx xx x x!!!x ",
" o o x x x x xxv xxx ",
" x x x x x!!!x ",
" xxx xxx xxx xxx o o x!!!!!!!!!!!!!!x vx ",
" x xxx x x xxx x x!!!!!!!!!!!!!!x ",
" x x xxxxxxxxxxxxxxxxxxxxxxx ",
" xx xx xxx ",
" xxx x x x x!!!x xxx ",
" x x x xxx x xxx x x ",
" x x xxx xxxxxxx xxxxx x ",
" x x x x x x ",
" x xx x x x x x ",
" x x |xxxx| |xxxx| xxx xxx x ",
" x xxx o o x x xxx x ",
" x xxxxx xx x xxx x!!!x x x ",
" x oxxxo x xxx x x x xxx xxx x ",
" x xxx xxxxxxxxxxxxx x oo x x oo x x oo xx xx xxx x ",
" x @ x x x!!x x!!!!x x!!!!x xx xx x x ",
" xxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ",
" ",
" "],
[" xxx x ",
" x ",
" xxxxx ",
" x ",
" x xxx ",
" o x x x ",
" o o oxxx x ",
" xxx x ",
" ! o ! xxxxx xxxxx xxxxx xxxxx xxxxx xxxxx xxxxx ",
" x x x x x x x x x x x x x x x ",
" x= o x x xxx x xxx x xxx x xxx x xxx x xxx x xxxxx ",
" x x x x x x x x x x x x x x x ",
" ! o ! o xxxx xxxxx xxxxx xxxxx xxxxx xxxxx xxxxxxx ",
" ",
" o xxx xx ",
" ",
" ",
" xx ",
" xxx xxx ",
" ",
" o x x ",
" xx xx ",
" xxx xxx xxx x x ",
" ",
" || ",
" xxxxxxxxxxx ",
" x x o xxxxxxxxx o xxxxxxxxx o xx x ",
" x x x x x x x || x x ",
" x @ xxxxx o xxxxx o xxxxx ",
" xxxxxxx xxxxx xx xx xxx ",
" x= = =x x xxx ",
" xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x!!!!!!!!!!!!!!!!!!!!!xxx!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!",
" xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
" "]
];
// Assumes the plan is valid (add validation for production)
function Level(plan) {
this.width = plan[0].length;
this.height = plan.length;
// Array of arrays, each position containing null or a character
this.grid = [];
// Contains all of the dynamic objects (lava, coin or player),
// along with their position and state
this.actors = [];
for (var y = 0; y < this.height; y++) {
var line = plan[y], gridLine = [];
for (var x = 0; x < this.width; x++) {
var ch = line[x], fieldType = null;
var Actor = actorChars[ch];
if (Actor)
// This constructs the referenced moving object in
// actorChars and pushes it to the actors array
this.actors.push(new Actor(new Vector(x, y), ch));
else if (ch == 'x')
// Wall
fieldType = 'wall';
else if (ch == '!')
// Stationary lava
fieldType = 'lava';
gridLine.push(fieldType);
}
this.grid.push(gridLine);
}
// Find the Player actor
this.player = this.actors.filter(function(actor) {
return actor.type == 'player';
})[0];
// Track whether the player has won or lost;
// finishDelay keeps the level active for a brief period of time
this.status = this.finishDelay = null;
}
// Figure out if the level is finished
Level.prototype.isFinished = function() {
return this.status != null && this.finishDelay < 0;
};
// Figure out the collision area of an actor
Level.prototype.obstacleAt = function(pos, size) {
var xStart = Math.floor(pos.x);
var xEnd = Math.ceil(pos.x + size.x);
var yStart = Math.floor(pos.y);
var yEnd = Math.ceil(pos.y + size.y);
// The upper and side bounds of the level return a wall
if (xStart < 0 || xEnd > this.width || yStart < 0)
return 'wall';
// The bottom bound returns lava
if (yEnd > this.height)
return 'lava';
// Check what's on the grid around the collision box
for (var y = yStart; y < yEnd; y++) {
for (var x = xStart; x < xEnd; x++) {
var fieldType = this.grid[y][x];
// returns 'wall' or 'lava'
if (fieldType) return fieldType;
}
}
};
// Track what actors overlap a given actor
Level.prototype.actorAt = function(actor) {
for (var i = 0; i < this.actors.length; i++) {
var other = this.actors[i];
if (other != actor &&
actor.pos.x + actor.size.x > other.pos.x &&
actor.pos.x < other.pos.x + other.size.x &&
actor.pos.y + actor.size.y > other.pos.y &&
actor.pos.y < other.pos.y + other.size.y)
return other;
}
};
// Time increment for Level.animate()
var maxStep = 0.05;
// Animate the level
// step will be given in seconds, keys is an object that
// contains info about the arrow keys the player has pressed.
Level.prototype.animate = function(step, keys) {
// Used for the delay at the end of a game
if (this.status != null)
this.finishDelay -= step;
while (step > 0) {
var thisStep = Math.min(step, maxStep);
this.actors.forEach(function(actor) {
actor.act(thisStep, this, keys);
}, this);
step -= thisStep;
}
};
// Handle collisions between actors
Level.prototype.playerTouched = function(type, actor) {
// Lava's been touched
if (type == 'lava' && this.status == null) {
this.status = 'lost';
this.finishDelay = 1;
} else if (type == 'coin') { // a coin's been touched
// Remove the coin that's been collected from actors array
this.actors = this.actors.filter(function(other) {
return other != actor;
});
// No more coins = you've won
if (!this.actors.some(function(actor) {
return actor.type == 'coin';
})) {
this.status = 'won';
this.finishDelay = 1;
}
}
}
var actorChars = {
'@': Player,
'o': Coin,
'=': Lava, '|': Lava, 'v': Lava
};
// Vector stores the position and size of an actor
function Vector(x, y) {
this.x = x; this.y = y;
}
Vector.prototype.plus = function(other) {
return new Vector(this.x + other.x, this.y + other.y);
}
Vector.prototype.times = function(factor) {
return new Vector(this.x * factor, this.y * factor);
}
// Player constructor
function Player(pos) {
// This properly aligns the bottom of the player
// to the square below (adjusts for player height)
this.pos = pos.plus(new Vector(0, -0.5));
this.size = new Vector(0.8, 1.5);
this.speed = new Vector(0, 0);
}
Player.prototype.type = 'player';
// X and Y movement are handled independently because
// a wall shouldn't stop the up and down motion of jumping
// and a floor shouldn't stop side to side movement
var playerXSpeed = 7;
Player.prototype.moveX = function(step, level, keys) {
this.speed.x = 0;
if (keys.left) this.speed.x -= playerXSpeed;
if (keys.right) this.speed.x += playerXSpeed;
var motion = new Vector(this.speed.x * step, 0);
var newPos = this.pos.plus(motion);
var obstacle = level.obstacleAt(newPos, this.size);
if (obstacle)
level.playerTouched(obstacle);
else
this.pos = newPos;
};
var gravity = 30;
var jumpSpeed = 17;
Player.prototype.moveY = function(step, level, keys) {
this.speed.y += step * gravity;
var motion = new Vector(0, this.speed.y * step);
var newPos = this.pos.plus(motion);
var obstacle = level.obstacleAt(newPos, this.size);
if (obstacle) {
level.playerTouched(obstacle);
if (keys.up && this.speed.y > 0)
this.speed.y = -jumpSpeed;
else
this.speed.y = 0;
} else {
this.pos = newPos;
}
};
Player.prototype.act = function(step, level, keys) {
this.moveX(step, level, keys);
this.moveY(step, level, keys);
var otherActor = level.actorAt(this);
if (otherActor)
level.playerTouched(otherActor.type, otherActor);
// Losing animation
if (level.status == 'lost') {
this.pos.y += step;
this.size.y -=step;
}
};
// Lava constructor
function Lava(pos, ch) {
this.pos = pos;
this.size = new Vector(1, 1);
if (ch == "=") {
// I'm guessing that speed will be added to this.pos
// in a moving method added later
this.speed = new Vector(2, 0);
} else if (ch == '|') {
this.speed = new Vector(0, 2);
} else if (ch == 'v') {
this.speed = new Vector(0, 3);
this.repeatPos = pos;
}
}
Lava.prototype.type = 'lava';
// Action
Lava.prototype.act = function(step, level) {
var newPos = this.pos.plus(this.speed.times(step));
if (!level.obstacleAt(newPos, this.size))
this.pos = newPos;
else if (this.repeatPos)
this.pos = this.repeatPos;
else
this.speed = this.speed.times(-1);
};
// Coin constructor
function Coin(pos) {
this.basePos = this.pos = pos.plus(new Vector(0.2, 0.1));
this.size = new Vector(0.6, 0.6);
this.wobble = Math.random() * Math.PI * 2;
}
Coin.prototype.type = 'coin';
var wobbleSpeed = 8, wobbleDist = 0.07;
// Action
Coin.prototype.act = function(step) {
this.wobble += step * wobbleSpeed;
var wobblePos = Math.sin(this.wobble) * wobbleDist;
this.pos = this.basePos.plus(new Vector(0, wobblePos));
};
// Helper function that creates an element
// and gives it a class
function elt(name, className) {
var elt = document.createElement(name);
if (className) elt.className = className;
return elt;
}
// Tracking keypresses for player movement
var arrowCodes = {37: 'left', 38: 'up', 39: 'right'};
function trackKeys(codes) {
var pressed = Object.create(null);
function handler(event) {
if (codes.hasOwnProperty(event.keyCode)) {
var down = event.type == 'keydown';
pressed[codes[event.keyCode]] = down;
event.preventDefault();
}
}
addEventListener('keydown', handler);
addEventListener('keyup', handler);
pressed.unregister = function() {
removeEventListener('keydown', handler);
removeEventListener('keyup', handler);
};
return pressed;
}
// Run the animation
function runAnimation(frameFunc) {
var lastTime = null;
function frame(time) {
var stop = false;
if (lastTime != null) {
var timeStep = Math.min(time - lastTime, 100) / 1000;
stop = frameFunc(timeStep) === false;
}
lastTime = time;
if (!stop)
requestAnimationFrame(frame);
}
requestAnimationFrame(frame);
}
// Run the level
var arrows = trackKeys(arrowCodes);
function runLevel(level, Display, andThen) {
var display = new Display(document.body, level);
// Used for storing pause state of the game
var running = 'yes';
function handleKey(event) {
if (event.keyCode == 27) {
if (running == 'no') {
running = 'yes';
runAnimation(animation);
} else if (running == 'pausing') {
running = 'yes';
} else if (running == 'yes') {
running = 'pausing';
}
}
}
addEventListener('keydown', handleKey);
function animation(step) {
if (running == 'pausing') {
running = 'no';
return false;
}
level.animate(step, arrows);
display.drawFrame(step);
if (level.isFinished()) {
display.clear();
// Remove the watch on the esc key
//removeEventListener('keydown', handleKey);
// Unregister the arrow key listeners
//arrows.unregister();
if (andThen)
andThen(level.status);
return false;
}
}
runAnimation(animation);
}
// Run the game
function runGame(plans, Display) {
var lives = 3;
var livesSpan = document.getElementById('lives');
var gameStatus = document.getElementById('status');
function startLevel(n) {
livesSpan.textContent = lives;
runLevel(new Level(plans[n]), Display, function(status) {
if (status == 'lost') {
lives--;
if (lives == 0) {
gameStatus.textContent = 'Game Over';
console.log('Game over');
}
else
startLevel(n);
}
else if (n < plans.length - 1)
startLevel(n + 1);
else
console.log('You win!');
});
}
startLevel(0);
}
// DOMDisplay uses the DOM to draw the program out
function DOMDisplay(parent, level) {
this.wrap = parent.appendChild(elt('div', 'game'));
this.level = level;
// Background is drawn only once
this.wrap.appendChild(this.drawBackground());
// The actorLayer is animated in the drawFrame() method
this.actorLayer = null;
this.drawFrame();
}
// Set the scale of 1 grid unit
var scale = 20;
// Draw the background
DOMDisplay.prototype.drawBackground = function() {
var table = elt('table', 'background');
table.style.width = this.level.width * scale + 'px';
this.level.grid.forEach(function(row) {
var rowElt = table.appendChild(elt('tr'));
rowElt.style.height = scale + 'px';
row.forEach(function(type) {
rowElt.appendChild(elt('td', type));
});
});
return table;
};
// Draw the actors
DOMDisplay.prototype.drawActors = function() {
var wrap = elt('div');
this.level.actors.forEach(function(actor) {
var rect = wrap.appendChild(elt('div', 'actor ' + actor.type));
rect.style.width = actor.size.x * scale + 'px';
rect.style.height = actor.size.y * scale + 'px';
rect.style.left = actor.pos.x * scale + 'px';
rect.style.top = actor.pos.y * scale + 'px';
});
return wrap;
};
// Redraw the actors
DOMDisplay.prototype.drawFrame = function() {
if (this.actorLayer)
this.wrap.removeChild(this.actorLayer);
this.actorLayer = this.wrap.appendChild(this.drawActors());
// The status class is used to style the player based on
// the state of the game (won or lost)
this.wrap.className = 'game ' + (this.level.status || '');
this.scrollPlayerIntoView();
};
// Make sure the player's always on screen
DOMDisplay.prototype.scrollPlayerIntoView = function() {
var width = this.wrap.clientWidth;
var height = this.wrap.clientHeight;
var margin = width / 3;
// The viewport
var left = this.wrap.scrollLeft, right = left + width;
var top = this.wrap.scrollTop, bottom = top + height;
// center makes use of the Vector methods defined earlier
var player = this.level.player;
var center = player.pos.plus(player.size.times(0.5))
.times(scale);
if (center.x < left + margin)
this.wrap.scrollLeft = center.x - margin;
else if (center.x > right - margin)
this.wrap.scrollLeft = center.x + margin - width;
if (center.y < top + margin)
this.wrap.scrollTop = center.y - margin;
else if (center.y > bottom - margin)
this.wrap.scrollTop = center.y + margin - height;
}
// Clear the level
DOMDisplay.prototype.clear = function() {
this.wrap.parentNode.removeChild(this.wrap);
};
// Canvas API helper function
function flipHorizontally(context, around) {
context.translate(around, 0);
context.scale(-1, 1);
context.translate(-around, 0);
}
// Use Canvas API to draw game
function CanvasDisplay(parent, level) {
// Set up the canvas element
this.canvas = document.createElement('canvas');
this.canvas.width = Math.min(1000, level.width * scale);
this.canvas.height = Math.min(1000, level.height * scale);
this.canvas.style.display = 'block';
this.canvas.style.margin = '200px auto 0';
parent.appendChild(this.canvas);
this.cx = this.canvas.getContext('2d');
this.level = level;
// Uses the step size passed to drawFrame()
this.animationTime = 0;
this.flipPlayer = false;
this.viewport = {
left: 0,
top: 0,
width: this.canvas.width / scale,
height: this.canvas.height / scale
};
this.drawFrame(0);
}
CanvasDisplay.prototype.clear = function() {
this.canvas.parentNode.removeChild(this.canvas);
};
// Draw the frame
CanvasDisplay.prototype.drawFrame = function(step) {
this.animationTime += step;
// Update the current player position for the viewport
this.updateViewport();
// Clear current frame
this.clearDisplay();
// Draw the background
this.drawBackground();
// Draw the actors
this.drawActors();
};
// Scrolls the viewport depending on the player position
CanvasDisplay.prototype.updateViewport = function() {
var view = this.viewport, margin = view.width / 3;
var player = this.level.player;
var center = player.pos.plus(player.size.times(0.5));
// Compare the center.x of player to the viewport
// Player is less than the left of the viewport plus margin
if (center.x < view.left + margin)
// Scroll left until less than 0
view.left = Math.max(center.x - margin, 0);
// Player is further right than the right of the viewport plus margin
else if (center.x > view.left + view.width - margin)
// Scroll right until greater than the edge of the level
view.left = Math.min(center.x + margin - view.width,
this.level.width - view.width);
if (center.y < view.top + margin)
view.top = Math.max(center.y - margin, 0);
else if (center.y > view.top + view.height - margin)
view.top = Math.min(center.y + margin - view.height,
this.level.height - view.height);
};
CanvasDisplay.prototype.clearDisplay = function() {
if (this.level.status == 'won')
this.cx.fillStyle = 'rgb(68, 191, 255)';
else if (this.level.status == 'lost')
this.cx.fillStyle = 'rgb(44, 136, 214)';
else
this.cx.fillStyle = 'rgb(52, 166, 251)';
this.cx.fillRect(0, 0,
this.canvas.width, this.canvas.height);
};
var otherSprites = document.createElement('img');
otherSprites.src = 'http://eloquentjavascript.net/img/sprites.png';
// Draw the background
CanvasDisplay.prototype.drawBackground = function() {
var view = this.viewport;
var xStart = Math.floor(view.left);
var xEnd = Math.ceil(view.left + view.width);
var yStart = Math.floor(view.top);
var yEnd = Math.ceil(view.top + view.height);
for (var y = yStart; y < yEnd; y++) {
for (var x = xStart; x < xEnd; x++) {
var tile = this.level.grid[y][x];
if (tile == null) continue;
var screenX = (x - view.left) * scale;
var screenY = (y - view.top) * scale;
var tileX = tile == 'lava' ? scale : 0;
this.cx.drawImage(otherSprites,
tileX, 0, scale, scale,
screenX, screenY, scale, scale);
}
}
};
// Draw the player (called by drawActors())
var playerSprites = document.createElement('img');
playerSprites.src = 'http://eloquentjavascript.net/img/player.png';
var playerXOverlap = 4;
CanvasDisplay.prototype.drawPlayer = function(x, y, width, height) {
var sprite = 8, player = this.level.player;
width += playerXOverlap * 2;
x -= playerXOverlap;
if (player.speed.x != 0)
this.flipPlayer = player.speed.x < 0;
if (player.speed.y != 0)
sprite = 9;
else if (player.speed.x != 0)
sprite = Math.floor(this.animationTime * 12) % 8;
this.cx.save();
if (this.flipPlayer)
flipHorizontally(this.cx, x + width / 2);
this.cx.drawImage(playerSprites,
sprite * width, 0, width, height,
x, y, width, height);
this.cx.restore();
}
// Draw the actors
CanvasDisplay.prototype.drawActors = function() {
this.level.actors.forEach(function(actor) {
var width = actor.size.x * scale;
var height = actor.size.y * scale;
var x = (actor.pos.x - this.viewport.left) * scale;
var y = (actor.pos.y - this.viewport.top) * scale;
if (actor.type == 'player') {
this.drawPlayer(x, y, width, height);
} else {
var tileX = (actor.type == 'coin' ? 2 : 1) * scale;
this.cx.drawImage(otherSprites,
tileX, 0, width, height,
x, y, width, height);
}
}, this);
};
// Run game with DOMDisplay
// runGame(GAME_LEVELS, DOMDisplay);
// Run game with CanvasDisplay
runGame(GAME_LEVELS, CanvasDisplay);
</script>
</body>
</html>
作者：梦三岁ii
链接：https://www.jianshu.com/p/b5fbc0dd23a9
来源：简书
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
