fengchuanyu 1 неделя назад
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253567b67a

+ 52 - 0
3_JavaScript/练习17_斐波纳契.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Document</title>
+</head>
+<body>
+    <script>
+        // 1 1 2 3 5 8 
+        function Fibonacci(n){
+            if(n<3){
+                return 1;
+            }else{
+                // 前两项
+                var a = 1;
+                // 前一项
+                var b = 1;
+                for(var i=3;i<=n;i++){
+                    var c = a + b;
+                    a = b;
+                    b = c;
+                }
+                return b;
+            }
+        }
+        // console.log(Fibonacci(6))
+
+        function Fibonacci2(n){
+            if(n<3){
+                return 1;
+            }else{
+                var arr = [1,1];
+                for(var i=3;i<=n;i++){
+                    arr[i-1] = arr[i-2] + arr[i-3];
+                }
+                return arr[n-1]
+            }
+        }
+        // console.log(Fibonacci2(6));
+
+
+        function Fibonacci3(n){
+            if(n<3){
+                return 1;
+            }
+            return Fibonacci3(n-1) + Fibonacci3(n-2);
+        }
+        console.log(Fibonacci3(6));
+    </script>
+</body>
+</html>

+ 28 - 0
3_JavaScript/练习18_派的近似值.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Document</title>
+</head>
+<body>
+    <script>
+        function f(n){
+            var a = Math.pow(-1,n-1) * (1/(2*n-1));
+            return a;
+        }
+
+        function f2(n){
+            var sum = 0;
+            for(var i=1;i<=n;i++){
+                sum += f(i);
+            }
+            return sum*4
+        }
+        console.log(f2(100));
+        console.log(f2(500));
+        console.log(f2(1000));
+        console.log(f2(10000));
+    </script>
+</body>
+</html>

+ 34 - 0
3_JavaScript/练习19_计算游戏的获胜率.html

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+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Document</title>
+</head>
+<body>
+    <script>
+        function randomNum(){
+            var a = Math.random();
+            // 随机数最小值 0.000000000000001
+            // 随机数最大值 0.999999999999999
+            a = a * 9 +1;
+            return Math.floor(a) 
+        }
+        var win = 0;
+        function play(){
+            var a = randomNum();
+            var b = randomNum();
+            var c = randomNum();
+            console.log(a,b,c);
+            if(a == 8 || b == 8 || c == 8){
+                win++;
+            }
+        }
+
+        for(var i=0;i<10;i++){
+            play();
+        }
+        console.log(win/10*100+"%")
+    </script>   
+</body>
+</html>